python cheatsheet
1.0.0
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1. Koleksi: List , Dictionary , Set , Tuple , Range , Enumerate , Iterator , Generator .
2. Jenis: Type , String , Regular_Exp , Format , Numbers , Combinatorics , Datetime .
3. Sintaks: Args , Inline , Import , Decorator , Class , Duck_Types , Enum , Exception .
4. Sistem: Exit , Print , Input , Command_Line_Arguments , Open , Path , OS_Commands .
5.Data: JSON , Pickle , CSV , SQLite , Bytes , Struct , Array , Memory_View , Deque .
6. Lanjutan: Operator , Match_Stmt , Logging , Introspection , Threading , Coroutines .
7. Perpustakaan: Progress_Bar , Plot , Table , Console_App , GUI , Scraping , Web , Profile .
8. Multimedia: NumPy , Image , Animation , Audio , Synthesizer , Pygame , Pandas , Plotly .
if __name__ == '__main__' : # Skips next line if file was imported.
main () # Runs `def main(): ...` function. < list > = [ < el_1 > , < el_2 > , ...] # Creates new list. Also list(<collection>). < el > = < list > [ index ] # First index is 0. Last -1. Allows assignments.
< list > = < list > [ < slice > ] # Also <list>[from_inclusive : to_exclusive : ±step]. < list > . append ( < el > ) # Appends element to the end. Also <list> += [<el>].
< list > . extend ( < collection > ) # Appends elements to the end. Also <list> += <coll>. < list > . sort () # Sorts elements in ascending order.
< list > . reverse () # Reverses the list in-place.
< list > = sorted ( < collection > ) # Returns new list with sorted elements.
< iter > = reversed ( < list > ) # Returns reversed iterator of elements. < el > = max ( < collection > ) # Returns largest element. Also min(<el_1>, ...).
< num > = sum ( < collection > ) # Returns sum of elements. Also math.prod(<coll>). elementwise_sum = [ sum ( pair ) for pair in zip ( list_a , list_b )]
sorted_by_second = sorted ( < collection > , key = lambda el : el [ 1 ])
sorted_by_both = sorted ( < collection > , key = lambda el : ( el [ 1 ], el [ 0 ]))
flatter_list = list ( itertools . chain . from_iterable ( < list > )) < int > = len ( < list > ) # Returns number of items. Also works on dict, set and string.
< int > = < list > . count ( < el > ) # Returns number of occurrences. Also `if <el> in <coll>: ...`.
< int > = < list > . index ( < el > ) # Returns index of the first occurrence or raises ValueError.
< el > = < list > . pop () # Removes and returns item from the end or at index if passed.
< list > . insert ( < int > , < el > ) # Inserts item at index and moves the rest to the right.
< list > . remove ( < el > ) # Removes first occurrence of the item or raises ValueError.
< list > . clear () # Removes all items. Also works on dictionary and set. < dict > = { key_1 : val_1 , key_2 : val_2 , ...} # Use `<dict>[key]` to get or set the value. < view > = < dict > . keys () # Collection of keys that reflects changes.
< view > = < dict > . values () # Collection of values that reflects changes.
< view > = < dict > . items () # Coll. of key-value tuples that reflects chgs. value = < dict > . get ( key , default = None ) # Returns default if key is missing.
value = < dict > . setdefault ( key , default = None ) # Returns and writes default if key is missing.
< dict > = collections . defaultdict ( < type > ) # Returns a dict with default value `<type>()`.
< dict > = collections . defaultdict ( lambda : 1 ) # Returns a dict with default value 1. < dict > = dict ( < collection > ) # Creates a dict from coll. of key-value pairs.
< dict > = dict ( zip ( keys , values )) # Creates a dict from two collections.
< dict > = dict . fromkeys ( keys [, value ]) # Creates a dict from collection of keys. < dict > . update ( < dict > ) # Adds items. Replaces ones with matching keys.
value = < dict > . pop ( key ) # Removes item or raises KeyError if missing.
{ k for k , v in < dict > . items () if v == value } # Returns set of keys that point to the value.
{ k : v for k , v in < dict > . items () if k in keys } # Filters the dictionary by keys. > >> from collections import Counter
> >> counter = Counter ([ 'blue' , 'blue' , 'blue' , 'red' , 'red' ])
> >> counter [ 'yellow' ] += 1
> >> print ( counter . most_common ())
[( 'blue' , 3 ), ( 'red' , 2 ), ( 'yellow' , 1 )] < set > = { < el_1 > , < el_2 > , ...} # Use `set()` for empty set. < set > . add ( < el > ) # Or: <set> |= {<el>}
< set > . update ( < collection > [, ...]) # Or: <set> |= <set> < set > = < set > . union ( < coll . > ) # Or: <set> | <set>
< set > = < set > . intersection ( < coll . > ) # Or: <set> & <set>
< set > = < set > . difference ( < coll . > ) # Or: <set> - <set>
< set > = < set > . symmetric_difference ( < coll . > ) # Or: <set> ^ <set>
< bool > = < set > . issubset ( < coll . > ) # Or: <set> <= <set>
< bool > = < set > . issuperset ( < coll . > ) # Or: <set> >= <set> < el > = < set > . pop () # Raises KeyError if empty.
< set > . remove ( < el > ) # Raises KeyError if missing.
< set > . discard ( < el > ) # Doesn't raise an error. < frozenset > = frozenset ( < collection > )Tuple adalah daftar yang tidak dapat diubah dan dapat di-hash.
< tuple > = () # Empty tuple.
< tuple > = ( < el > ,) # Or: <el>,
< tuple > = ( < el_1 > , < el_2 > [, ...]) # Or: <el_1>, <el_2> [, ...]Subkelas Tuple dengan elemen bernama.
> >> from collections import namedtuple
> >> Point = namedtuple ( 'Point' , 'x y' )
> >> p = Point ( 1 , y = 2 ); p
Point ( x = 1 , y = 2 )
> >> p [ 0 ]
1
> >> p . x
1
> >> getattr ( p , 'y' )
2 Urutan bilangan bulat yang tidak dapat diubah dan dapat di-hash.
< range > = range ( stop ) # range(to_exclusive)
< range > = range ( start , stop ) # range(from_inclusive, to_exclusive)
< range > = range ( start , stop , ± step ) # range(from_inclusive, to_exclusive, ±step_size) > >> [ i for i in range ( 3 )]
[ 0 , 1 , 2 ] for i , el in enumerate ( < coll > , start = 0 ): # Returns next element and its index on each pass.
... < iter > = iter ( < collection > ) # `iter(<iter>)` returns unmodified iterator.
< iter > = iter ( < function > , to_exclusive ) # A sequence of return values until 'to_exclusive'.
< el > = next ( < iter > [, default ]) # Raises StopIteration or returns 'default' on end.
< list > = list ( < iter > ) # Returns a list of iterator's remaining elements. import itertools as it < iter > = it . count ( start = 0 , step = 1 ) # Returns updated value endlessly. Accepts floats.
< iter > = it . repeat ( < el > [, times ]) # Returns element endlessly or 'times' times.
< iter > = it . cycle ( < collection > ) # Repeats the sequence endlessly. < iter > = it . chain ( < coll > , < coll > [, ...]) # Empties collections in order (figuratively).
< iter > = it . chain . from_iterable ( < coll > ) # Empties collections inside a collection in order. < iter > = it . islice ( < coll > , to_exclusive ) # Only returns first 'to_exclusive' elements.
< iter > = it . islice ( < coll > , from_inc , …) # `to_exclusive, +step_size`. Indices can be None. def count ( start , step ):
while True :
yield start
start += step > >> counter = count ( 10 , 2 )
> >> next ( counter ), next ( counter ), next ( counter )
( 10 , 12 , 14 ) < type > = type ( < el > ) # Or: <el>.__class__
< bool > = isinstance ( < el > , < type > ) # Or: issubclass(type(<el>), <type>) > >> type ( 'a' ), 'a' . __class__ , str
( < class 'str' > , < class 'str' > , < class 'str' > ) from types import FunctionType , MethodType , LambdaType , GeneratorType , ModuleTypeSetiap kelas dasar abstrak menentukan satu set subkelas virtual. Kelas-kelas ini kemudian dikenali oleh isinstance() dan issubclass() sebagai subkelas ABC, meskipun sebenarnya bukan. ABC juga dapat secara manual memutuskan apakah suatu kelas tertentu merupakan subkelas virtualnya atau tidak, biasanya berdasarkan metode yang telah diimplementasikan oleh kelas tersebut. Misalnya, Iterable ABC mencari metode iter(), sedangkan Collection ABC mencari iter(), berisi() dan len().
> >> from collections . abc import Iterable , Collection , Sequence
> >> isinstance ([ 1 , 2 , 3 ], Iterable )
True +------------------+------------+------------+------------+
| | Iterable | Collection | Sequence |
+------------------+------------+------------+------------+
| list, range, str | yes | yes | yes |
| dict, set | yes | yes | |
| iter | yes | | |
+------------------+------------+------------+------------+
> >> from numbers import Number , Complex , Real , Rational , Integral
> >> isinstance ( 123 , Number )
True +--------------------+----------+----------+----------+----------+----------+
| | Number | Complex | Real | Rational | Integral |
+--------------------+----------+----------+----------+----------+----------+
| int | yes | yes | yes | yes | yes |
| fractions.Fraction | yes | yes | yes | yes | |
| float | yes | yes | yes | | |
| complex | yes | yes | | | |
| decimal.Decimal | yes | | | | |
+--------------------+----------+----------+----------+----------+----------+
Urutan karakter yang tidak dapat diubah.
< str > = < str > . strip () # Strips all whitespace characters from both ends.
< str > = < str > . strip ( '<chars>' ) # Strips passed characters. Also lstrip/rstrip(). < list > = < str > . split () # Splits on one or more whitespace characters.
< list > = < str > . split ( sep = None , maxsplit = - 1 ) # Splits on 'sep' str at most 'maxsplit' times.
< list > = < str > . splitlines ( keepends = False ) # On [nrfvx1c-x1ex85u2028u2029] and rn.
< str > = < str > . join ( < coll_of_strings > ) # Joins elements using string as a separator. < bool > = < sub_str > in < str > # Checks if string contains the substring.
< bool > = < str > . startswith ( < sub_str > ) # Pass tuple of strings for multiple options.
< int > = < str > . find ( < sub_str > ) # Returns start index of the first match or -1.
< int > = < str > . index ( < sub_str > ) # Same, but raises ValueError if there's no match. < str > = < str > . lower () # Changes the case. Also upper/capitalize/title().
< str > = < str > . replace ( old , new [, count ]) # Replaces 'old' with 'new' at most 'count' times.
< str > = < str > . translate ( < table > ) # Use `str.maketrans(<dict>)` to generate table. < str > = chr ( < int > ) # Converts int to Unicode character.
< int > = ord ( < str > ) # Converts Unicode character to int.'unicodedata.normalize("NFC", <str>)' pada string seperti 'Motörhead' sebelum membandingkannya dengan string lain, karena 'ö' dapat disimpan sebagai satu atau dua karakter.'NFC' mengubah karakter tersebut menjadi satu karakter, sedangkan 'NFD' mengubahnya menjadi dua. < bool > = < str > . isdecimal () # Checks for [0-9]. Also [०-९] and [٠-٩].
< bool > = < str > . isdigit () # Checks for [²³¹…] and isdecimal().
< bool > = < str > . isnumeric () # Checks for [¼½¾…], [零〇一…] and isdigit().
< bool > = < str > . isalnum () # Checks for [a-zA-Z…] and isnumeric().
< bool > = < str > . isprintable () # Checks for [ !#$%…] and isalnum().
< bool > = < str > . isspace () # Checks for [ tnrfvx1c-x1fx85xa0…]. Fungsi untuk pencocokan ekspresi reguler.
import re
< str > = re . sub ( r'<regex>' , new , text , count = 0 ) # Substitutes all occurrences with 'new'.
< list > = re . findall ( r'<regex>' , text ) # Returns all occurrences as strings.
< list > = re . split ( r'<regex>' , text , maxsplit = 0 ) # Add brackets around regex to keep matches.
< Match > = re . search ( r'<regex>' , text ) # First occurrence of the pattern or None.
< Match > = re . match ( r'<regex>' , text ) # Searches only at the beginning of the text.
< iter > = re . finditer ( r'<regex>' , text ) # Returns all occurrences as Match objects.'flags=re.IGNORECASE' dapat digunakan dengan semua fungsi.'flags=re.MULTILINE' membuat '^' dan '$' cocok dengan awal/akhir setiap baris.'flags=re.DOTALL' menghasilkan '.' juga menerima 'n' .'re.compile(<regex>)' mengembalikan objek Pola dengan metode sub(), findall(), … < str > = < Match > . group () # Returns the whole match. Also group(0).
< str > = < Match > . group ( 1 ) # Returns part inside the first brackets.
< tuple > = < Match > . groups () # Returns all bracketed parts.
< int > = < Match > . start () # Returns start index of the match.
< int > = < Match > . end () # Returns exclusive end index of the match. 'd' == '[0-9]' # Also [०-९…]. Matches a decimal character.
'w' == '[a-zA-Z0-9_]' # Also [ª²³…]. Matches an alphanumeric or _.
's' == '[ t n r f v ]' # Also [x1c-x1f…]. Matches a whitespace.'flags=re.ASCII' digunakan. Ini membatasi pencocokan urutan khusus ke 128 karakter Unicode pertama dan juga mencegah 's' menerima 'x1c' , 'x1d' , 'x1e' dan 'x1f' (karakter yang tidak dapat dicetak yang membagi teks menjadi file, tabel, baris, dan bidang, masing-masing).<str> = f ' {<el_1>}, {<el_2>} ' # Curly brackets can also contain expressions.
<str> = ' {}, {} ' .format(<el_1>, <el_2>) # Or: '{0}, {a}'.format(<el_1>, a=<el_2>)
<str> = ' %s, %s ' % (<el_1>, <el_2>) # Redundant and inferior C-style formatting. > >> Person = collections . namedtuple ( 'Person' , 'name height' )
> >> person = Person ( 'Jean-Luc' , 187 )
> >> f' { person . name } is { person . height / 100 } meters tall.'
'Jean-Luc is 1.87 meters tall.'{ < el > : < 10 } # '<el> '
{ < el > : ^ 10 } # ' <el> '
{ < el > : > 10 } # ' <el>'
{ < el > :. < 10 } # '<el>......'
{ < el > : 0 } # '<el>''format(<el>, "<options>")' .f'{<el>:{<str/int>}[…]}' .'=' ke ekspresi akan menambahkannya ke output: f'{1+1=}' mengembalikan '1+1=2' .'!r' ke ekspresi akan mengubah objek menjadi string dengan memanggil metode repr()-nya.{ 'abcde' : 10 } # 'abcde '
{ 'abcde' : 10.3 } # 'abc '
{ 'abcde' : .3 } # 'abc'
{ 'abcde' !r: 10 } # "'abcde' "{ 123456 : 10 } # ' 123456'
{ 123456 : 10 ,} # ' 123,456'
{ 123456 : 10_ } # ' 123_456'
{ 123456 : + 10 } # ' +123456'
{ 123456 : = + 10 } # '+ 123456'
{ 123456 : } # ' 123456'
{ - 123456 : } # '-123456'{ 1.23456 : 10.3 } # ' 1.23'
{ 1.23456 : 10.3 f } # ' 1.235'
{ 1.23456 : 10.3 e } # ' 1.235e+00'
{ 1.23456 : 10.3 % } # ' 123.456%' +--------------+----------------+----------------+----------------+----------------+
| | {<float>} | {<float>:f} | {<float>:e} | {<float>:%} |
+--------------+----------------+----------------+----------------+----------------+
| 0.000056789 | '5.6789e-05' | '0.000057' | '5.678900e-05' | '0.005679%' |
| 0.00056789 | '0.00056789' | '0.000568' | '5.678900e-04' | '0.056789%' |
| 0.0056789 | '0.0056789' | '0.005679' | '5.678900e-03' | '0.567890%' |
| 0.056789 | '0.056789' | '0.056789' | '5.678900e-02' | '5.678900%' |
| 0.56789 | '0.56789' | '0.567890' | '5.678900e-01' | '56.789000%' |
| 5.6789 | '5.6789' | '5.678900' | '5.678900e+00' | '567.890000%' |
| 56.789 | '56.789' | '56.789000' | '5.678900e+01' | '5678.900000%' |
+--------------+----------------+----------------+----------------+----------------+
+--------------+----------------+----------------+----------------+----------------+
| | {<float>:.2} | {<float>:.2f} | {<float>:.2e} | {<float>:.2%} |
+--------------+----------------+----------------+----------------+----------------+
| 0.000056789 | '5.7e-05' | '0.00' | '5.68e-05' | '0.01%' |
| 0.00056789 | '0.00057' | '0.00' | '5.68e-04' | '0.06%' |
| 0.0056789 | '0.0057' | '0.01' | '5.68e-03' | '0.57%' |
| 0.056789 | '0.057' | '0.06' | '5.68e-02' | '5.68%' |
| 0.56789 | '0.57' | '0.57' | '5.68e-01' | '56.79%' |
| 5.6789 | '5.7' | '5.68' | '5.68e+00' | '567.89%' |
| 56.789 | '5.7e+01' | '56.79' | '5.68e+01' | '5678.90%' |
+--------------+----------------+----------------+----------------+----------------+
'{<float>:g}' adalah '{<float>:.6}' dengan nol yang dihilangkan, eksponen dimulai dari '1e+06' .'{6.5:.0f}' menjadi '6' dan '{7.5:.0f}' menjadi '8' ..5 , .25 , …).{ 90 : c } # 'Z'. Unicode character with value 90.
{ 90 : b } # '1011010'. Number 90 in binary.
{ 90 : X } # '5A'. Number 90 in uppercase hexadecimal. < int > = int ( < float / str / bool > ) # Or: math.trunc(<float>)
< float > = float ( < int / str / bool > ) # Or: <int/float>e±<int>
< complex > = complex ( real = 0 , imag = 0 ) # Or: <int/float> ± <int/float>j
< Fraction > = fractions . Fraction ( 0 , 1 ) # Or: Fraction(numerator=0, denominator=1)
< Decimal > = decimal . Decimal ( < str / int > ) # Or: Decimal((sign, digits, exponent))'int(<str>)' dan 'float(<str>)' meningkatkan ValueError pada string yang salah format.'1.1 + 2.2 != 3.3' .'math.isclose(<float>, <float>)' .'decimal.getcontext().prec = <int>' . < num > = pow ( < num > , < num > ) # Or: <number> ** <number>
< num > = abs ( < num > ) # <float> = abs(<complex>)
< num > = round ( < num > [, ± ndigits ]) # `round(126, -1) == 130` from math import e , pi , inf , nan , isinf , isnan # `<el> == nan` is always False.
from math import sin , cos , tan , asin , acos , atan # Also: degrees, radians.
from math import log , log10 , log2 # Log can accept base as second arg. from statistics import mean , median , variance # Also: stdev, quantiles, groupby. from random import random , randint , choice # Also: shuffle, gauss, triangular, seed.
< float > = random () # A float inside [0, 1).
< int > = randint ( from_inc , to_inc ) # An int inside [from_inc, to_inc].
< el > = choice ( < sequence > ) # Keeps the sequence intact. < int > = ± 0 b < bin > # Or: ±0x<hex>
< int > = int ( '±<bin>' , 2 ) # Or: int('±<hex>', 16)
< int > = int ( '±0b<bin>' , 0 ) # Or: int('±0x<hex>', 0)
< str > = bin ( < int > ) # Returns '[-]0b<bin>'. Also hex(). < int > = < int > & < int > # And (0b1100 & 0b1010 == 0b1000).
< int > = < int > | < int > # Or (0b1100 | 0b1010 == 0b1110).
< int > = < int > ^ < int > # Xor (0b1100 ^ 0b1010 == 0b0110).
< int > = < int > < < n_bits # Left shift. Use >> for right.
< int > = ~ < int > # Not. Also -<int> - 1. import itertools as it > >> list ( it . product ([ 0 , 1 ], repeat = 3 ))
[( 0 , 0 , 0 ), ( 0 , 0 , 1 ), ( 0 , 1 , 0 ), ( 0 , 1 , 1 ),
( 1 , 0 , 0 ), ( 1 , 0 , 1 ), ( 1 , 1 , 0 ), ( 1 , 1 , 1 )] > >> list ( it . product ( 'abc' , 'abc' )) # a b c
[( 'a' , 'a' ), ( 'a' , 'b' ), ( 'a' , 'c' ), # a x x x
( 'b' , 'a' ), ( 'b' , 'b' ), ( 'b' , 'c' ), # b x x x
( 'c' , 'a' ), ( 'c' , 'b' ), ( 'c' , 'c' )] # c x x x > >> list ( it . combinations ( 'abc' , 2 )) # a b c
[( 'a' , 'b' ), ( 'a' , 'c' ), # a . x x
( 'b' , 'c' )] # b . . x > >> list ( it . combinations_with_replacement ( 'abc' , 2 )) # a b c
[( 'a' , 'a' ), ( 'a' , 'b' ), ( 'a' , 'c' ), # a x x x
( 'b' , 'b' ), ( 'b' , 'c' ), # b . x x
( 'c' , 'c' )] # c . . x > >> list ( it . permutations ( 'abc' , 2 )) # a b c
[( 'a' , 'b' ), ( 'a' , 'c' ), # a . x x
( 'b' , 'a' ), ( 'b' , 'c' ), # b x . x
( 'c' , 'a' ), ( 'c' , 'b' )] # c x x . Menyediakan kelas 'date', 'time', 'datetime' dan 'timedelta'. Semuanya tidak dapat diubah dan dapat di-hash.
# $ pip3 install python-dateutil
from datetime import date , time , datetime , timedelta , timezone
import zoneinfo , dateutil . tz < D > = date ( year , month , day ) # Only accepts valid dates from 1 to 9999 AD.
< T > = time ( hour = 0 , minute = 0 , second = 0 ) # Also: `microsecond=0, tzinfo=None, fold=0`.
< DT > = datetime ( year , month , day , hour = 0 ) # Also: `minute=0, second=0, microsecond=0, …`.
< TD > = timedelta ( weeks = 0 , days = 0 , hours = 0 ) # Also: `minutes=0, seconds=0, microseconds=0`.'fold=1' berarti lintasan kedua jika waktu melompat mundur selama satu jam.'[±D, ]H:MM:SS[.…]' dan total_detik() float semua detik.'<D/DT>.weekday()' untuk mendapatkan hari dalam seminggu sebagai int, dengan Monday menjadi 0. < D / DTn > = D / DT . today () # Current local date or naive DT. Also DT.now().
< DTa > = DT . now ( < tzinfo > ) # Aware DT from current time in passed timezone.'<DTn>.time()' , '<DTa>.time()' atau '<DTa>.timetz()' . < tzinfo > = timezone . utc # London without daylight saving time (DST).
< tzinfo > = timezone ( < timedelta > ) # Timezone with fixed offset from UTC.
< tzinfo > = dateutil . tz . tzlocal () # Local timezone with dynamic offset from UTC.
< tzinfo > = zoneinfo . ZoneInfo ( '<iana_key>' ) # 'Continent/City_Name' zone with dynamic offset.
< DTa > = < DT > . astimezone ([ < tzinfo > ]) # Converts DT to the passed or local fixed zone.
< Ta / DTa > = < T / DT > . replace ( tzinfo = < tzinfo > ) # Changes object's timezone without conversion.'> pip3 install tzdata' . < D / T / DT > = D / T / DT . fromisoformat ( < str > ) # Object from ISO string. Raises ValueError.
< DT > = DT . strptime ( < str > , '<format>' ) # Datetime from str, according to format.
< D / DTn > = D / DT . fromordinal ( < int > ) # D/DT from days since the Gregorian NYE 1.
< DTn > = DT . fromtimestamp ( < float > ) # Local naive DT from seconds since the Epoch.
< DTa > = DT . fromtimestamp ( < float > , < tz > ) # Aware datetime from seconds since the Epoch.'YYYY-MM-DD' , 'HH:MM:SS.mmmuuu[±HH:MM]' , atau keduanya dipisahkan oleh karakter arbitrer. Semua bagian setelah jam kerja adalah opsional.'1970-01-01 00:00 UTC' , '1970-01-01 01:00 CET' , ... < str > = < D / T / DT > . isoformat ( sep = 'T' ) # Also `timespec='auto/hours/minutes/seconds/…'`.
< str > = < D / T / DT > . strftime ( '<format>' ) # Custom string representation of the object.
< int > = < D / DT > . toordinal () # Days since Gregorian NYE 1, ignoring time and tz.
< float > = < DTn > . timestamp () # Seconds since the Epoch, from local naive DT.
< float > = < DTa > . timestamp () # Seconds since the Epoch, from aware datetime. > >> dt = datetime . strptime ( '2025-08-14 23:39:00.00 +0200' , '%Y-%m-%d %H:%M:%S.%f %z' )
> >> dt . strftime ( "%dth of %B '%y (%a), %I:%M %p %Z" )
"14th of August '25 (Thu), 11:39 PM UTC+02:00"'%z' menerima '±HH[:]MM' dan mengembalikan '±HHMM' atau string kosong jika datetime naif.'%Z' menerima 'UTC/GMT' dan kode zona waktu lokal dan mengembalikan nama zona waktu, 'UTC[±HH:MM]' jika zona waktu tidak bernama, atau string kosong jika tanggalwaktu naif. < bool > = < D / T / DTn > > < D / T / DTn > # Ignores time jumps (fold attribute). Also ==.
< bool > = < DTa > > < DTa > # Ignores jumps if they share tz object. Broken ==.
< TD > = < D / DTn > - < D / DTn > # Ignores jumps. Convert to UTC for actual delta.
< TD > = < DTa > - < DTa > # Ignores jumps if they share tzinfo object.
< D / DT > = < D / DT > ± < TD > # Returned datetime can fall into missing hour.
< TD > = < TD > * < float > # Also: <TD> = abs(<TD>) and <TD> = <TD> ±% <TD>.
< float > = < TD > / < TD > # E.g. how many hours are in TD. Also //, divmod(). func ( < positional_args > ) # func(0, 0)
func ( < keyword_args > ) # func(x=0, y=0)
func ( < positional_args > , < keyword_args > ) # func(0, y=0) def func ( < nondefault_args > ): ... # def func(x, y): ...
def func ( < default_args > ): ... # def func(x=0, y=0): ...
def func ( < nondefault_args > , < default_args > ): ... # def func(x, y=0): ...Splat memperluas koleksi menjadi argumen posisi, sementara splatty-splat memperluas kamus menjadi argumen kata kunci.
args = ( 1 , 2 )
kwargs = { 'x' : 3 , 'y' : 4 , 'z' : 5 }
func ( * args , ** kwargs ) func ( 1 , 2 , x = 3 , y = 4 , z = 5 )Splat menggabungkan nol atau lebih argumen posisi ke dalam tuple, sementara splatty-splat menggabungkan nol atau lebih argumen kata kunci ke dalam kamus.
def add ( * a ):
return sum ( a ) > >> add ( 1 , 2 , 3 )
6 def f ( * args ): ... # f(1, 2, 3)
def f ( x , * args ): ... # f(1, 2, 3)
def f ( * args , z ): ... # f(1, 2, z=3) def f ( ** kwargs ): ... # f(x=1, y=2, z=3)
def f ( x , ** kwargs ): ... # f(x=1, y=2, z=3) | f(1, y=2, z=3) def f ( * args , ** kwargs ): ... # f(x=1, y=2, z=3) | f(1, y=2, z=3) | f(1, 2, z=3) | f(1, 2, 3)
def f ( x , * args , ** kwargs ): ... # f(x=1, y=2, z=3) | f(1, y=2, z=3) | f(1, 2, z=3) | f(1, 2, 3)
def f ( * args , y , ** kwargs ): ... # f(x=1, y=2, z=3) | f(1, y=2, z=3) def f ( * , x , y , z ): ... # f(x=1, y=2, z=3)
def f ( x , * , y , z ): ... # f(x=1, y=2, z=3) | f(1, y=2, z=3)
def f ( x , y , * , z ): ... # f(x=1, y=2, z=3) | f(1, y=2, z=3) | f(1, 2, z=3) < list > = [ * < coll . > [, ...]] # Or: list(<collection>) [+ ...]
< tuple > = ( * < coll . > , [...]) # Or: tuple(<collection>) [+ ...]
< set > = { * < coll . > [, ...]} # Or: set(<collection>) [| ...]
< dict > = { ** < dict > [, ...]} # Or: <dict> | ... head , * body , tail = < coll . > # Head or tail can be omitted. < func > = lambda : < return_value > # A single statement function.
< func > = lambda < arg_1 > , < arg_2 > : < return_value > # Also allows default arguments. < list > = [ i + 1 for i in range ( 10 )] # Or: [1, 2, ..., 10]
< iter > = ( i for i in range ( 10 ) if i > 5 ) # Or: iter([6, 7, 8, 9])
< set > = { i + 5 for i in range ( 10 )} # Or: {5, 6, ..., 14}
< dict > = { i : i * 2 for i in range ( 10 )} # Or: {0: 0, 1: 2, ..., 9: 18} > >> [ l + r for l in 'abc' for r in 'abc' ] # Inner loop is on the right side.
[ 'aa' , 'ab' , 'ac' , ..., 'cc' ] from functools import reduce < iter > = map ( lambda x : x + 1 , range ( 10 )) # Or: iter([1, 2, ..., 10])
< iter > = filter ( lambda x : x > 5 , range ( 10 )) # Or: iter([6, 7, 8, 9])
< obj > = reduce ( lambda out , x : out + x , range ( 10 )) # Or: 45 < bool > = any ( < collection > ) # Is `bool(<el>)` True for any el?
< bool > = all ( < collection > ) # True for all? Also True if empty. < obj > = < exp > if < condition > else < exp > # Only one expression is evaluated. > >> [ a if a else 'zero' for a in ( 0 , 1 , 2 , 3 )] # `any([0, '', [], None]) == False`
[ 'zero' , 1 , 2 , 3 ] from collections import namedtuple
Point = namedtuple ( 'Point' , 'x y' ) # Creates a tuple's subclass.
point = Point ( 0 , 0 ) # Returns its instance. from enum import Enum
Direction = Enum ( 'Direction' , 'N E S W' ) # Creates an enum.
direction = Direction . N # Returns its member. from dataclasses import make_dataclass
Player = make_dataclass ( 'Player' , [ 'loc' , 'dir' ]) # Creates a class.
player = Player ( point , direction ) # Returns its instance. Mekanisme yang membuat kode dalam satu file tersedia untuk file lain.
import < module > # Imports a built-in or '<module>.py'.
import < package > # Imports a built-in or '<package>/__init__.py'.
import < package > . < module > # Imports a built-in or '<package>/<module>.py'.'import <package>' tidak secara otomatis menyediakan akses ke modul paket kecuali modul tersebut diimpor secara eksplisit dalam skrip initnya.'from .[…][<pkg/module>[.…]] import <obj>' . Kami memiliki/mendapatkan penutupan dengan Python ketika fungsi bersarang mereferensikan nilai fungsi penutupnya dan kemudian fungsi penutup mengembalikan fungsi bersarang.
def get_multiplier ( a ):
def out ( b ):
return a * b
return out > >> multiply_by_3 = get_multiplier ( 3 )
> >> multiply_by_3 ( 10 )
30 from functools import partial
< function > = partial ( < function > [, < arg_1 > [, ...]]) > >> def multiply ( a , b ):
... return a * b
> >> multiply_by_3 = partial ( multiply , 3 )
> >> multiply_by_3 ( 10 )
30'defaultdict(<func>)' , 'iter(<func>, to_exc)' dan 'field(default_factory=<func>)' kelas data.Jika variabel ditugaskan ke mana saja dalam ruang lingkup, maka dianggap sebagai variabel lokal, kecuali jika dinyatakan sebagai 'global' atau 'nonlokal'.
def get_counter ():
i = 0
def out ():
nonlocal i
i += 1
return i
return out > >> counter = get_counter ()
> >> counter (), counter (), counter ()
( 1 , 2 , 3 ) @ decorator_name
def function_that_gets_passed_to_decorator ():
...Dekorator yang mencetak nama fungsi setiap kali fungsi tersebut dipanggil.
from functools import wraps
def debug ( func ):
@ wraps ( func )
def out ( * args , ** kwargs ):
print ( func . __name__ )
return func ( * args , ** kwargs )
return out
@ debug
def add ( x , y ):
return x + y'add.__name__' akan mengembalikan 'out' .Dekorator yang menyimpan nilai kembalian fungsi dalam cache. Semua argumen fungsi harus dapat di-hash.
from functools import cache
@ cache
def fib ( n ):
return n if n < 2 else fib ( n - 2 ) + fib ( n - 1 )'fib.cache_clear()' , atau gunakan dekorator '@lru_cache(maxsize=<int>)' sebagai gantinya.'sys.setrecursionlimit(<int>)' .Dekorator yang menerima argumen dan mengembalikan dekorator normal yang menerima fungsi.
from functools import wraps
def debug ( print_result = False ):
def decorator ( func ):
@ wraps ( func )
def out ( * args , ** kwargs ):
result = func ( * args , ** kwargs )
print ( func . __name__ , result if print_result else '' )
return result
return out
return decorator
@ debug ( print_result = True )
def add ( x , y ):
return x + y'@debug' untuk menghiasi fungsi add() tidak akan berfungsi di sini, karena debug kemudian akan menerima fungsi add() sebagai argumen 'print_result'. Namun dekorator dapat secara manual memeriksa apakah argumen yang mereka terima adalah suatu fungsi dan bertindak sesuai dengan itu. Templat untuk membuat objek yang ditentukan pengguna.
class MyClass :
def __init__ ( self , a ):
self . a = a
def __str__ ( self ):
return str ( self . a )
def __repr__ ( self ):
class_name = self . __class__ . __name__
return f' { class_name } ( { self . a !r } )'
@ classmethod
def get_class_name ( cls ):
return cls . __name__ > >> obj = MyClass ( 1 )
> >> obj . a , str ( obj ), repr ( obj )
( 1 , '1' , 'MyClass(1)' )'@staticmethod' tidak menerima 'self' atau 'cls' sebagai argumen pertamanya. print ( < obj > )
f' { < obj > } '
logging . warning ( < obj > )
csv . writer ( < file > ). writerow ([ < obj > ])
raise Exception ( < obj > ) print / str / repr ([ < obj > ])
print / str / repr ({ < obj > : < obj > })
f' { < obj > !r } '
Z = dataclasses . make_dataclass ( 'Z' , [ 'a' ]); print / str / repr ( Z ( < obj > ))
> >> < obj > class Person :
def __init__ ( self , name ):
self . name = name
class Employee ( Person ):
def __init__ ( self , name , staff_num ):
super (). __init__ ( name )
self . staff_num = staff_num class A : pass
class B : pass
class C ( A , B ): passMRO menentukan urutan kelas induk dilintasi saat mencari metode atau atribut:
> >> C . mro ()
[ < class 'C' > , < class 'A' > , < class 'B' > , < class 'object' > ]'def f() -> <type>:' ). from collections import abc
< name > : < type > [ | ...] [ = < obj > ] # `|` since 3.10.
< name > : list / set / abc . Iterable / abc . Sequence [ < type > ] [ = < obj > ] # Since 3.9.
< name > : dict / tuple [ < type > , ...] [ = < obj > ] # Since 3.9.Dekorator yang menggunakan variabel kelas untuk menghasilkan metode khusus init(), repr() dan eq().
from dataclasses import dataclass , field , make_dataclass
@ dataclass ( order = False , frozen = False )
class < class_name > :
< attr_name > : < type >
< attr_name > : < type > = < default_value >
< attr_name > : list / dict / set = field ( default_factory = list / dict / set )'order=True' dan tidak dapat diubah dengan 'frozen=True' .'<attr_name>: list = []' akan membuat daftar yang dibagikan di antara semua instance. Argumen 'default_factory'-nya dapat berupa panggilan apa pun.'typing.Any' . Point = make_dataclass ( 'Point' , [ 'x' , 'y' ])
Point = make_dataclass ( 'Point' , [( 'x' , float ), ( 'y' , float )])
Point = make_dataclass ( 'Point' , [( 'x' , float , 0 ), ( 'y' , float , 0 )])Cara Pythonic mengimplementasikan pengambil dan penyetel.
class Person :
@ property
def name ( self ):
return ' ' . join ( self . _name )
@ name . setter
def name ( self , value ):
self . _name = value . split () > >> person = Person ()
> >> person . name = ' t Guido van Rossum n '
> >> person . name
'Guido van Rossum'Mekanisme yang membatasi objek pada atribut yang tercantum dalam 'slot', mengurangi jejak memorinya.
class MyClassWithSlots :
__slots__ = [ 'a' ]
def __init__ ( self ):
self . a = 1 from copy import copy , deepcopy
< object > = copy / deepcopy ( < object > )Tipe bebek adalah tipe implisit yang menentukan serangkaian metode khusus. Objek apa pun yang memiliki metode yang ditentukan dianggap sebagai anggota tipe bebek tersebut.
'id(self) == id(other)' , yang sama dengan 'self is other' . class MyComparable :
def __init__ ( self , a ):
self . a = a
def __eq__ ( self , other ):
if isinstance ( other , type ( self )):
return self . a == other . a
return NotImplemented'id(self)' tidak akan berfungsi. class MyHashable :
def __init__ ( self , a ):
self . _a = a
@ property
def a ( self ):
return self . _a
def __eq__ ( self , other ):
if isinstance ( other , type ( self )):
return self . a == other . a
return NotImplemented
def __hash__ ( self ):
return hash ( self . a )'key=locale.strxfrm' ke sort() setelah menjalankan 'locale.setlocale(locale.LC_COLLATE, "en_US.UTF-8")' . from functools import total_ordering
@ total_ordering
class MySortable :
def __init__ ( self , a ):
self . a = a
def __eq__ ( self , other ):
if isinstance ( other , type ( self )):
return self . a == other . a
return NotImplemented
def __lt__ ( self , other ):
if isinstance ( other , type ( self )):
return self . a < other . a
return NotImplemented class Counter :
def __init__ ( self ):
self . i = 0
def __next__ ( self ):
self . i += 1
return self . i
def __iter__ ( self ):
return self > >> counter = Counter ()
> >> next ( counter ), next ( counter ), next ( counter )
( 1 , 2 , 3 )'callable(<obj>)' atau 'isinstance(<obj>, collections.abc.Callable)' untuk memeriksa apakah objek dapat dipanggil.'<function>' sebagai argumen, artinya '<callable>' . class Counter :
def __init__ ( self ):
self . i = 0
def __call__ ( self ):
self . i += 1
return self . i > >> counter = Counter ()
> >> counter (), counter (), counter ()
( 1 , 2 , 3 ) class MyOpen :
def __init__ ( self , filename ):
self . filename = filename
def __enter__ ( self ):
self . file = open ( self . filename )
return self . file
def __exit__ ( self , exc_type , exception , traceback ):
self . file . close () > >> with open ( 'test.txt' , 'w' ) as file :
... file . write ( 'Hello World!' )
> >> with MyOpen ( 'test.txt' ) as file :
... print ( file . read ())
Hello World ! class MyIterable :
def __init__ ( self , a ):
self . a = a
def __iter__ ( self ):
return iter ( self . a )
def __contains__ ( self , el ):
return el in self . a > >> obj = MyIterable ([ 1 , 2 , 3 ])
> >> [ el for el in obj ]
[ 1 , 2 , 3 ]
> >> 1 in obj
True'<iterable>' ketika menggunakan '<collection>' . class MyCollection :
def __init__ ( self , a ):
self . a = a
def __iter__ ( self ):
return iter ( self . a )
def __contains__ ( self , el ):
return el in self . a
def __len__ ( self ):
return len ( self . a ) class MySequence :
def __init__ ( self , a ):
self . a = a
def __iter__ ( self ):
return iter ( self . a )
def __contains__ ( self , el ):
return el in self . a
def __len__ ( self ):
return len ( self . a )
def __getitem__ ( self , i ):
return self . a [ i ]
def __reversed__ ( self ):
return reversed ( self . a )'abc.Iterable' dan 'abc.Collection' , ini bukan tipe bebek. Itulah sebabnya 'issubclass(MySequence, abc.Sequence)' akan mengembalikan False meskipun semua metode MySequence telah ditentukan. Namun ia mengenali list, tuple, range, str, bytes, bytearray, array, memoryview dan deque, karena mereka terdaftar sebagai subkelas virtual Sequence. from collections import abc
class MyAbcSequence ( abc . Sequence ):
def __init__ ( self , a ):
self . a = a
def __len__ ( self ):
return len ( self . a )
def __getitem__ ( self , i ):
return self . a [ i ] +------------+------------+------------+------------+--------------+
| | Iterable | Collection | Sequence | abc.Sequence |
+------------+------------+------------+------------+--------------+
| iter() | REQ | REQ | Yes | Yes |
| contains() | Yes | Yes | Yes | Yes |
| len() | | REQ | REQ | REQ |
| getitem() | | | REQ | REQ |
| reversed() | | | Yes | Yes |
| index() | | | | Yes |
| count() | | | | Yes |
+------------+------------+------------+------------+--------------+
'isinstance(<obj>, abc.Iterable)' untuk mengembalikan True, namun objek apa pun dengan getitem() akan bekerja dengan kode apa pun yang mengharapkan iterable.'<abc>.__abstractmethods__' untuk mendapatkan nama metode yang diperlukan. Kelas konstanta bernama disebut anggota.
from enum import Enum , auto class < enum_name > ( Enum ):
< member_name > = auto () # Increment of the last numeric value or 1.
< member_name > = < value > # Values don't have to be hashable.
< member_name > = < el_1 > , < el_2 > # Values can be collections (this is a tuple). < member > = < enum > . < member_name > # Returns a member. Raises AttributeError.
< member > = < enum > [ '<member_name>' ] # Returns a member. Raises KeyError.
< member > = < enum > ( < value > ) # Returns a member. Raises ValueError.
< str > = < member > . name # Returns member's name.
< obj > = < member > . value # Returns member's value. < list > = list ( < enum > ) # Returns enum's members.
< list > = [ a . name for a in < enum > ] # Returns enum's member names.
< list > = [ a . value for a in < enum > ] # Returns enum's member values. < enum > = type ( < member > ) # Returns member's enum.
< iter > = itertools . cycle ( < enum > ) # Returns endless iterator of members.
< member > = random . choice ( list ( < enum > )) # Returns a random member. Cutlery = Enum ( 'Cutlery' , 'FORK KNIFE SPOON' )
Cutlery = Enum ( 'Cutlery' , [ 'FORK' , 'KNIFE' , 'SPOON' ])
Cutlery = Enum ( 'Cutlery' , { 'FORK' : 1 , 'KNIFE' : 2 , 'SPOON' : 3 }) from functools import partial
LogicOp = Enum ( 'LogicOp' , { 'AND' : partial ( lambda l , r : l and r ),
'OR' : partial ( lambda l , r : l or r )}) try :
< code >
except < exception > :
< code > try :
< code_1 >
except < exception_a > :
< code_2_a >
except < exception_b > :
< code_2_b >
else :
< code_2_c >
finally :
< code_3 >'else' hanya akan dieksekusi jika blok 'try' tidak memiliki pengecualian.'finally' akan selalu dieksekusi (kecuali jika sinyal diterima).'signal.signal(signal_number, <func>)' . except < exception > : ...
except < exception > as < name > : ...
except ( < exception > , [...]): ...
except ( < exception > , [...]) as < name > : ...'traceback.print_exc()' untuk mencetak pesan kesalahan lengkap ke stderr.'print(<name>)' untuk mencetak penyebab pengecualian saja (argumennya).'logging.exception(<str>)' untuk mencatat pesan yang diteruskan, diikuti dengan pesan kesalahan lengkap dari pengecualian yang ditangkap. Untuk detailnya lihat pencatatan.'sys.exc_info()' untuk mendapatkan jenis pengecualian, objek, dan penelusuran balik dari pengecualian yang tertangkap. raise < exception >
raise < exception > ()
raise < exception > ( < obj > [, ...]) except < exception > [ as < name > ]:
...
raise arguments = < name > . args
exc_type = < name > . __class__
filename = < name > . __traceback__ . tb_frame . f_code . co_filename
func_name = < name > . __traceback__ . tb_frame . f_code . co_name
line = linecache . getline ( filename , < name > . __traceback__ . tb_lineno )
trace_str = '' . join ( traceback . format_tb ( < name > . __traceback__ ))
error_msg = '' . join ( traceback . format_exception ( type ( < name > ), < name > , < name > . __traceback__ )) BaseException
+-- SystemExit # Raised by the sys.exit() function.
+-- KeyboardInterrupt # Raised when the user hits the interrupt key (ctrl-c).
+-- Exception # User-defined exceptions should be derived from this class.
+-- ArithmeticError # Base class for arithmetic errors such as ZeroDivisionError.
+-- AssertionError # Raised by `assert <exp>` if expression returns false value.
+-- AttributeError # Raised when object doesn't have requested attribute/method.
+-- EOFError # Raised by input() when it hits an end-of-file condition.
+-- LookupError # Base class for errors when a collection can't find an item.
| +-- IndexError # Raised when a sequence index is out of range.
| +-- KeyError # Raised when a dictionary key or set element is missing.
+-- MemoryError # Out of memory. May be too late to start deleting variables.
+-- NameError # Raised when nonexistent name (variable/func/class) is used.
| +-- UnboundLocalError # Raised when local name is used before it's being defined.
+-- OSError # Errors such as FileExistsError/TimeoutError (see #Open).
| +-- ConnectionError # Errors such as BrokenPipeError/ConnectionAbortedError.
+-- RuntimeError # Raised by errors that don't fall into other categories.
| +-- NotImplementedEr… # Can be raised by abstract methods or by unfinished code.
| +-- RecursionError # Raised when the maximum recursion depth is exceeded.
+-- StopIteration # Raised when an empty iterator is passed to next().
+-- TypeError # When an argument of the wrong type is passed to function.
+-- ValueError # When argument has the right type but inappropriate value.
+-----------+------------+------------+------------+
| | List | Set | Dict |
+-----------+------------+------------+------------+
| getitem() | IndexError | | KeyError |
| pop() | IndexError | KeyError | KeyError |
| remove() | ValueError | KeyError | |
| index() | ValueError | | |
+-----------+------------+------------+------------+
raise TypeError ( 'Argument is of the wrong type!' )
raise ValueError ( 'Argument has the right type but an inappropriate value!' )
raise RuntimeError ( 'I am too lazy to define my own exception!' ) class MyError ( Exception ): pass
class MyInputError ( MyError ): pass Keluar dari penerjemah dengan memunculkan pengecualian SystemExit.
import sys
sys . exit () # Exits with exit code 0 (success).
sys . exit ( < int > ) # Exits with the passed exit code.
sys . exit ( < obj > ) # Prints to stderr and exits with 1. print ( < el_1 > , ..., sep = ' ' , end = ' n ' , file = sys . stdout , flush = False )'file=sys.stderr' untuk pesan tentang kesalahan.'flush=True' digunakan, atau program keluar. from pprint import pprint
pprint ( < collection > , width = 80 , depth = None , compact = False , sort_dicts = True ) < str > = input ( prompt = None ) import sys
scripts_path = sys . argv [ 0 ]
arguments = sys . argv [ 1 :] from argparse import ArgumentParser , FileType
p = ArgumentParser ( description = < str > ) # Returns a parser.
p . add_argument ( '-<short_name>' , '--<name>' , action = 'store_true' ) # Flag (defaults to False).
p . add_argument ( '-<short_name>' , '--<name>' , type = < type > ) # Option (defaults to None).
p . add_argument ( '<name>' , type = < type > , nargs = 1 ) # Mandatory first argument.
p . add_argument ( '<name>' , type = < type > , nargs = '+' ) # Mandatory remaining args.
p . add_argument ( '<name>' , type = < type > , nargs = '?/*' ) # Optional argument/s.
args = p . parse_args () # Exits on parsing error.
< obj > = args . < name > # Returns `<type>(<arg>)`.'help=<str>' untuk mengatur deskripsi argumen yang akan ditampilkan dalam pesan bantuan.'default=<obj>' untuk menyetel nilai default opsi atau argumen opsional.'type=FileType(<mode>)' untuk file. Menerima 'pengkodean', tetapi 'baris baru' adalah Tidak Ada. Membuka file dan mengembalikan objek file yang sesuai.
< file > = open ( < path > , mode = 'r' , encoding = None , newline = None )'encoding=None' berarti pengkodean default digunakan, yang bergantung pada platform. Praktik terbaik adalah menggunakan 'encoding="utf-8"' bila memungkinkan.'newline=None' berarti semua kombinasi akhir baris yang berbeda dikonversi menjadi 'n' saat dibaca, sedangkan saat ditulis semua karakter 'n' dikonversi ke pemisah baris default sistem.'newline=""' berarti tidak ada konversi yang terjadi, tetapi masukan masih dipecah menjadi beberapa bagian oleh readline() dan readlines() pada setiap 'n', 'r' dan 'rn'.'r' - Baca. Digunakan secara default.'w' - Tulis. Menghapus konten yang ada.'x' - Tulis atau gagal jika file sudah ada.'a' - Tambahkan. Membuat file baru jika tidak ada.'w+' - Membaca dan menulis. Menghapus konten yang ada.'r+' - Membaca dan menulis dari awal.'a+' - Membaca dan menulis dari akhir.'b' - Mode biner ( 'rb' , 'wb' , 'xb' , …).'FileNotFoundError' dapat dimunculkan saat membaca dengan 'r' atau 'r+' .'FileExistsError' dapat dimunculkan saat menulis dengan 'x' .'IsADirectoryError' dan 'PermissionError' dapat dimunculkan oleh siapa saja.'OSError' adalah kelas induk dari semua pengecualian yang terdaftar. < file > . seek ( 0 ) # Moves to the start of the file.
< file > . seek ( offset ) # Moves 'offset' chars/bytes from the start.
< file > . seek ( 0 , 2 ) # Moves to the end of the file.
< bin_file > . seek (± offset , origin ) # Origin: 0 start, 1 current position, 2 end. < str / bytes > = < file > . read ( size = - 1 ) # Reads 'size' chars/bytes or until EOF.
< str / bytes > = < file > . readline () # Returns a line or empty string/bytes on EOF.
< list > = < file > . readlines () # Returns a list of remaining lines.
< str / bytes > = next ( < file > ) # Returns a line using buffer. Do not mix. < file > . write ( < str / bytes > ) # Writes a string or bytes object.
< file > . writelines ( < collection > ) # Writes a coll. of strings or bytes objects.
< file > . flush () # Flushes write buffer. Runs every 4096/8192 B.
< file > . close () # Closes the file after flushing write buffer. def read_file ( filename ):
with open ( filename , encoding = 'utf-8' ) as file :
return file . readlines () def write_to_file ( filename , text ):
with open ( filename , 'w' , encoding = 'utf-8' ) as file :
file . write ( text ) import os , glob
from pathlib import Path < str > = os . getcwd () # Returns working dir. Starts as shell's $PWD.
< str > = os . path . join ( < path > , ...) # Joins two or more pathname components.
< str > = os . path . realpath ( < path > ) # Resolves symlinks and calls path.abspath(). < str > = os . path . basename ( < path > ) # Returns final component of the path.
< str > = os . path . dirname ( < path > ) # Returns path without the final component.
< tup . > = os . path . splitext ( < path > ) # Splits on last period of the final component. < list > = os . listdir ( path = '.' ) # Returns filenames located at the path.
< list > = glob . glob ( '<pattern>' ) # Returns paths matching the wildcard pattern. < bool > = os . path . exists ( < path > ) # Or: <Path>.exists()
< bool > = os . path . isfile ( < path > ) # Or: <DirEntry/Path>.is_file()
< bool > = os . path . isdir ( < path > ) # Or: <DirEntry/Path>.is_dir() < stat > = os . stat ( < path > ) # Or: <DirEntry/Path>.stat()
< num > = < stat > . st_mtime / st_size / … # Modification time, size in bytes, etc.Tidak seperti listdir(), scandir() mengembalikan objek DirEntry yang menyimpan cache isfile, isdir, dan pada Windows juga informasi stat, sehingga secara signifikan meningkatkan kinerja kode yang memerlukannya.
< iter > = os . scandir ( path = '.' ) # Returns DirEntry objects located at the path.
< str > = < DirEntry > . path # Returns the whole path as a string.
< str > = < DirEntry > . name # Returns final component as a string.
< file > = open ( < DirEntry > ) # Opens the file and returns a file object. < Path > = Path ( < path > [, ...]) # Accepts strings, Paths, and DirEntry objects.
< Path > = < path > / < path > [ / ...] # First or second path must be a Path object.
< Path > = < Path > . resolve () # Returns absolute path with resolved symlinks. < Path > = Path () # Returns relative CWD. Also Path('.').
< Path > = Path . cwd () # Returns absolute CWD. Also Path().resolve().
< Path > = Path . home () # Returns user's home directory (absolute).
< Path > = Path ( __file__ ). resolve () # Returns script's path if CWD wasn't changed. < Path > = < Path > . parent # Returns Path without the final component.
< str > = < Path > . name # Returns final component as a string.
< str > = < Path > . stem # Returns final component without extension.
< str > = < Path > . suffix # Returns final component's extension.
< tup . > = < Path > . parts # Returns all components as strings. < iter > = < Path > . iterdir () # Returns directory contents as Path objects.
< iter > = < Path > . glob ( '<pattern>' ) # Returns Paths matching the wildcard pattern. < str > = str ( < Path > ) # Returns path as a string.
< file > = open ( < Path > ) # Also <Path>.read/write_text/bytes(<args>). import os , shutil , subprocess os . chdir ( < path > ) # Changes the current working directory.
os . mkdir ( < path > , mode = 0o777 ) # Creates a directory. Permissions are in octal.
os . makedirs ( < path > , mode = 0o777 ) # Creates all path's dirs. Also `exist_ok=False`. shutil . copy ( from , to ) # Copies the file. 'to' can exist or be a dir.
shutil . copy2 ( from , to ) # Also copies creation and modification time.
shutil . copytree ( from , to ) # Copies the directory. 'to' must not exist. os . rename ( from , to ) # Renames/moves the file or directory.
os . replace ( from , to ) # Same, but overwrites file 'to' even on Windows.
shutil . move ( from , to ) # Rename() that moves into 'to' if it's a dir. os . remove ( < path > ) # Deletes the file.
os . rmdir ( < path > ) # Deletes the empty directory.
shutil . rmtree ( < path > ) # Deletes the directory. < pipe > = os . popen ( '<commands>' ) # Executes commands in sh/cmd. Returns combined stdout.
< str > = < pipe > . read ( size = - 1 ) # Reads 'size' chars or until EOF. Also readline/s().
< int > = < pipe > . close () # Returns None if last command exited with returncode 0. > >> subprocess . run ( 'bc' , input = '1 + 1 n ' , capture_output = True , text = True )
CompletedProcess ( args = 'bc' , returncode = 0 , stdout = '2 n ' , stderr = '' ) > >> from shlex import split
> >> os . popen ( 'echo 1 + 1 > test.in' )
> >> subprocess . run ( split ( 'bc -s' ), stdin = open ( 'test.in' ), stdout = open ( 'test.out' , 'w' ))
CompletedProcess ( args = [ 'bc' , '-s' ], returncode = 0 )
> >> open ( 'test.out' ). read ()
'2 n ' Format file teks untuk menyimpan kumpulan string dan angka.
import json
< str > = json . dumps ( < list / dict > ) # Converts collection to JSON string.
< coll > = json . loads ( < str > ) # Converts JSON string to collection. def read_json_file ( filename ):
with open ( filename , encoding = 'utf-8' ) as file :
return json . load ( file ) def write_to_json_file ( filename , list_or_dict ):
with open ( filename , 'w' , encoding = 'utf-8' ) as file :
json . dump ( list_or_dict , file , ensure_ascii = False , indent = 2 )Format file biner untuk menyimpan objek Python.
import pickle
< bytes > = pickle . dumps ( < object > ) # Converts object to bytes object.
< object > = pickle . loads ( < bytes > ) # Converts bytes object to object. def read_pickle_file ( filename ):
with open ( filename , 'rb' ) as file :
return pickle . load ( file ) def write_to_pickle_file ( filename , an_object ):
with open ( filename , 'wb' ) as file :
pickle . dump ( an_object , file )Format file teks untuk menyimpan spreadsheet.
import csv < reader > = csv . reader ( < file > ) # Also: `dialect='excel', delimiter=','`.
< list > = next ( < reader > ) # Returns next row as a list of strings.
< list > = list ( < reader > ) # Returns a list of remaining rows.'newline=""' , atau baris baru yang tertanam di dalam kolom yang dikutip tidak akan ditafsirkan dengan benar! < writer > = csv . writer ( < file > ) # Also: `dialect='excel', delimiter=','`.
< writer > . writerow ( < collection > ) # Encodes objects using `str(<el>)`.
< writer > . writerows ( < coll_of_coll > ) # Appends multiple rows.'newline=""' , atau 'r' akan ditambahkan di depan setiap 'n' pada platform yang menggunakan akhiran baris 'rn'!'mode="a"' untuk menambahkannya atau 'mode="w"' untuk menimpanya.'dialect' - Parameter utama yang menetapkan nilai default. String atau objek 'csv.Dialect'.'delimiter' - String satu karakter yang digunakan untuk memisahkan bidang.'lineterminator' - Bagaimana penulis mengakhiri baris. Pembaca di-hardcode menjadi 'n', 'r', 'rn'.'quotechar' - Karakter untuk mengutip bidang yang berisi karakter khusus.'escapechar' - Karakter untuk keluar dari quotechars.'doublequote' - Apakah kutipan di dalam bidang digandakan atau diloloskan.'quoting' - 0: Seperlunya, 1: Semua, 2: Semua kecuali angka yang dibaca sebagai float, 3: Tidak ada.'skipinitialspace' - Apakah karakter spasi di awal bidang dihilangkan oleh pembaca. +------------------+--------------+--------------+--------------+
| | excel | excel-tab | unix |
+------------------+--------------+--------------+--------------+
| delimiter | ',' | 't' | ',' |
| lineterminator | 'rn' | 'rn' | 'n' |
| quotechar | '"' | '"' | '"' |
| escapechar | None | None | None |
| doublequote | True | True | True |
| quoting | 0 | 0 | 1 |
| skipinitialspace | False | False | False |
+------------------+--------------+--------------+--------------+
def read_csv_file ( filename , ** csv_params ):
with open ( filename , encoding = 'utf-8' , newline = '' ) as file :
return list ( csv . reader ( file , ** csv_params )) def write_to_csv_file ( filename , rows , mode = 'w' , ** csv_params ):
with open ( filename , mode , encoding = 'utf-8' , newline = '' ) as file :
writer = csv . writer ( file , ** csv_params )
writer . writerows ( rows )Mesin database tanpa server yang menyimpan setiap database ke dalam filenya sendiri.
import sqlite3
< conn > = sqlite3 . connect ( < path > ) # Opens existing or new file. Also ':memory:'.
< conn > . close () # Closes connection. Discards uncommitted data. < cursor > = < conn > . execute ( '<query>' ) # Can raise a subclass of sqlite3.Error.
< tuple > = < cursor > . fetchone () # Returns next row. Also next(<cursor>).
< list > = < cursor > . fetchall () # Returns remaining rows. Also list(<cursor>). < conn > . execute ( '<query>' ) # Can raise a subclass of sqlite3.Error.
< conn > . commit () # Saves all changes since the last commit.
< conn > . rollback () # Discards all changes since the last commit. with < conn > : # Exits the block with commit() or rollback(),
< conn > . execute ( '<query>' ) # depending on whether any exception occurred. < conn > . execute ( '<query>' , < list / tuple > ) # Replaces '?'s in query with values.
< conn > . execute ( '<query>' , < dict / namedtuple > ) # Replaces ':<key>'s with values.
< conn > . executemany ( '<query>' , < coll_of_coll > ) # Runs execute() multiple times. Nilai sebenarnya tidak disimpan dalam contoh ini karena 'conn.commit()' dihilangkan!
> >> conn = sqlite3 . connect ( 'test.db' )
> >> conn . execute ( 'CREATE TABLE person (person_id INTEGER PRIMARY KEY, name, height)' )
> >> conn . execute ( 'INSERT INTO person VALUES (NULL, ?, ?)' , ( 'Jean-Luc' , 187 )). lastrowid
1
> >> conn . execute ( 'SELECT * FROM person' ). fetchall ()
[( 1 , 'Jean-Luc' , 187 )]Pustaka untuk berinteraksi dengan berbagai sistem DB melalui SQL, rangkaian metode, atau ORM.
# $ pip3 install sqlalchemy
from sqlalchemy import create_engine , text
< engine > = create_engine ( '<url>' ) # Url: 'dialect://user:password@host/dbname'.
< conn > = < engine > . connect () # Creates a connection. Also <conn>.close().
< cursor > = < conn > . execute ( text ( '<query>' ), …) # `<dict>`. Replaces ':<key>'s with values.
with < conn > . begin (): ... # Exits the block with commit or rollback. +-----------------+--------------+----------------------------------+
| Dialect | pip3 install | Dependencies |
+-----------------+--------------+----------------------------------+
| mysql | mysqlclient | www.pypi.org/project/mysqlclient |
| postgresql | psycopg2 | www.pypi.org/project/psycopg2 |
| mssql | pyodbc | www.pypi.org/project/pyodbc |
| oracle+oracledb | oracledb | www.pypi.org/project/oracledb |
+-----------------+--------------+----------------------------------+
Objek bytes adalah urutan byte tunggal yang tidak dapat diubah. Versi yang bisa diubah disebut bytearray.
< bytes > = b'<str>' # Only accepts ASCII characters and x00-xff.
< int > = < bytes > [ index ] # Returns an int in range from 0 to 255.
< bytes > = < bytes > [ < slice > ] # Returns bytes even if it has only one element.
< bytes > = < bytes > . join ( < coll_of_bytes > ) # Joins elements using bytes as a separator. < bytes > = bytes ( < coll_of_ints > ) # Ints must be in range from 0 to 255.
< bytes > = bytes ( < str > , 'utf-8' ) # Encodes the string. Also <str>.encode().
< bytes > = bytes . fromhex ( '<hex>' ) # Hex pairs can be separated by whitespaces.
< bytes > = < int > . to_bytes ( n_bytes , …) # `byteorder='big/little', signed=False`. < list > = list ( < bytes > ) # Returns ints in range from 0 to 255.
< str > = str ( < bytes > , 'utf-8' ) # Returns a string. Also <bytes>.decode().
< str > = < bytes > . hex () # Returns hex pairs. Accepts `sep=<str>`.
< int > = int . from_bytes ( < bytes > , …) # `byteorder='big/little', signed=False`. def read_bytes ( filename ):
with open ( filename , 'rb' ) as file :
return file . read () def write_bytes ( filename , bytes_obj ):
with open ( filename , 'wb' ) as file :
file . write ( bytes_obj ) from struct import pack , unpack
< bytes > = pack ( '<format>' , < el_1 > [, ...]) # Packs objects according to format string.
< tuple > = unpack ( '<format>' , < bytes > ) # Use iter_unpack() to get iterator of tuples. > >> pack ( '>hhl' , 1 , 2 , 3 )
b' x00 x01 x00 x02 x00 x00 x00 x03 '
> >> unpack ( '>hhl' , b' x00 x01 x00 x02 x00 x00 x00 x03 ' )
( 1 , 2 , 3 )'=' - Urutan byte sistem (biasanya little-endian).'<' - Little-endian (yaitu byte paling signifikan terlebih dahulu).'>' - Big-endian (juga '!' ). 'c' - Objek byte dengan satu elemen. Untuk pad byte gunakan 'x' .'<n>s' - Objek byte dengan n elemen (tidak dipengaruhi oleh urutan byte). 'b' - karakter (1/1)'h' - pendek (2/2)'i' - ke dalam (2/4)'l' - panjang (4/4)'q' - panjang panjang (8/8) 'f' - mengapung (4/4)'d' - ganda (8/8) Daftar yang hanya dapat menampung nomor dari tipe yang telah ditentukan sebelumnya. Jenis yang tersedia dan ukuran minimumnya dalam byte tercantum di atas. Ukuran jenis dan urutan byte selalu ditentukan oleh sistem, namun byte setiap elemen dapat dibalik dengan metode byteswap().
from array import array < array > = array ( '<typecode>' , < coll_of_nums > ) # Creates array from collection of numbers.
< array > = array ( '<typecode>' , < bytes > ) # Writes passed bytes to array's memory.
< array > = array ( '<typecode>' , < array > ) # Treats passed array as a sequence of numbers.
< array > . fromfile ( < file > , n_items ) # Appends file's contents to array's memory. < bytes > = bytes ( < array > ) # Returns a copy of array's memory.
< file > . write ( < array > ) # Writes array's memory to the binary file. Objek urutan yang menunjuk ke memori objek mirip byte lainnya. Setiap elemen dapat mereferensikan satu atau beberapa byte berturut-turut, bergantung pada format. Urutan dan jumlah elemen dapat diubah dengan mengiris.
< mview > = memoryview ( < bytes / bytearray / array > ) # Immutable if bytes is passed, else mutable.
< obj > = < mview > [ index ] # Returns int or float. Bytes if format is 'c'.
< mview > = < mview > [ < slice > ] # Returns memoryview with rearranged elements.
< mview > = < mview > . cast ( '<typecode>' ) # Only works between B/b/c and other types.
< mview > . release () # Releases memory buffer of the base object. < bytes > = bytes ( < mview > ) # Returns a new bytes object. Also bytearray().
< bytes > = < bytes > . join ( < coll_of_mviews > ) # Joins memoryviews using bytes as a separator.
< array > = array ( '<typecode>' , < mview > ) # Treats memoryview as a sequence of numbers.
< file > . write ( < mview > ) # Writes `bytes(<mview>)` to the binary file. < list > = list ( < mview > ) # Returns a list of ints, floats, or bytes.
< str > = str ( < mview > , 'utf-8' ) # Treats memoryview as a bytes object.
< str > = < mview > . hex () # Returns hex pairs. Accepts `sep=<str>`. Daftar dengan penambahan dan pop yang efisien dari kedua sisi. Diucapkan "dek".
from collections import deque < deque > = deque ( < collection > ) # Use `maxlen=<int>` to set size limit.
< deque > . appendleft ( < el > ) # Opposite element is dropped if full.
< deque > . extendleft ( < collection > ) # Passed collection gets reversed.
< deque > . rotate ( n = 1 ) # Last element becomes first.
< el > = < deque > . popleft () # Raises IndexError if deque is empty. Modul fungsi yang menyediakan fungsionalitas operator. Fungsi diurutkan dan dikelompokkan berdasarkan prioritas operator, dari yang paling mengikat hingga yang paling mengikat. Operator logika dan aritmatika pada baris 1, 3 dan 5 diurutkan berdasarkan prioritas juga dalam satu grup.
import operator as op < bool > = op . not_ ( < obj > ) # or, and, not (or/and missing)
< bool > = op . eq / ne / lt / ge / is_ / is_not / contains ( < obj > , < obj > ) # ==, !=, <, >=, is, is not, in
< obj > = op . or_ / xor / and_ ( < int / set > , < int / set > ) # |, ^, &
< int > = op . lshift / rshift ( < int > , < int > ) # <<, >>
< obj > = op . add / sub / mul / truediv / floordiv / mod ( < obj > , < obj > ) # +, -, *, /, //, %
< num > = op . neg / invert ( < num > ) # -, ~
< num > = op . pow ( < num > , < num > ) # **
< func > = op . itemgetter / attrgetter / methodcaller ( < obj > [, ...]) # [index/key], .name, .name([…]) elementwise_sum = map ( op . add , list_a , list_b )
sorted_by_second = sorted ( < coll > , key = op . itemgetter ( 1 ))
sorted_by_both = sorted ( < coll > , key = op . itemgetter ( 1 , 0 ))
first_element = op . methodcaller ( 'pop' , 0 )( < list > )'x < y < z' akan dikonversi menjadi '(x < y) and (y < z) '. Mengeksekusi blok pertama dengan pola yang cocok. Ditambahkan dalam Python 3.10.
match < object / expression > :
case < pattern > [ if < condition > ]:
< code >
... < value_pattern > = 1 / 'abc' / True / None / math . pi # Matches the literal or a dotted name.
< class_pattern > = < type > () # Matches any object of that type (or ABC).
< wildcard_patt > = _ # Matches any object. Useful in last case.
< capture_patt > = < name > # Matches any object and binds it to name.
< as_pattern > = < pattern > as < name > # Binds match to name. Also <type>(<name>).
< or_pattern > = < pattern > | < pattern > [ | ...] # Matches any of the patterns.
< sequence_patt > = [ < pattern > , ...] # Matches sequence with matching items.
< mapping_patt > = { < value_pattern > : < patt > , ...} # Matches dictionary with matching items.
< class_pattern > = < type > ( < attr_name >= < patt > , ...) # Matches object with matching attributes.'*<name>' dan '**<name>' dalam pola urutan/pemetaan untuk mengikat item yang tersisa.'|' > 'as' > ',' ). > >> from pathlib import Path
> >> match Path ( '/home/gto/python-cheatsheet/README.md' ):
... case Path (
... parts = [ '/' , 'home' , user , * _ ]
... ) as p if p . name . lower (). startswith ( 'readme' ) and p . is_file ():
... print ( f' { p . name } is a readme file that belongs to user { user } .' )
'README.md is a readme file that belongs to user gto.' import logging as log log . basicConfig ( filename = < path > , level = 'DEBUG' ) # Configures the root logger (see Setup).
log . debug / info / warning / error / critical ( < str > ) # Sends message to the root logger.
< Logger > = log . getLogger ( __name__ ) # Returns logger named after the module.
< Logger > . < level > ( < str > ) # Sends message to the logger.
< Logger > . exception ( < str > ) # Error() that appends caught exception. log . basicConfig (
filename = None , # Logs to stderr or appends to file.
format = '%(levelname)s:%(name)s:%(message)s' , # Add '%(asctime)s' for local datetime.
level = log . WARNING , # Drops messages with lower priority.
handlers = [ log . StreamHandler ( sys . stderr )] # Uses FileHandler if filename is set.
) < Formatter > = log . Formatter ( '<format>' ) # Creates a Formatter.
< Handler > = log . FileHandler ( < path > , mode = 'a' ) # Creates a Handler. Also `encoding=None`.
< Handler > . setFormatter ( < Formatter > ) # Adds Formatter to the Handler.
< Handler > . setLevel ( < int / str > ) # Processes all messages by default.
< Logger > . addHandler ( < Handler > ) # Adds Handler to the Logger.
< Logger > . setLevel ( < int / str > ) # What is sent to its/ancestors' handlers.
< Logger > . propagate = < bool > # Cuts off ancestors' handlers if False.'<parent>.<name>' .'filter(<LogRecord>)' (atau metode itu sendiri) dapat ditambahkan ke logger dan penangan melalui addFilter(). Pesan dihilangkan jika filter() mengembalikan nilai yang salah. > >> logger = log . getLogger ( 'my_module' )
> >> handler = log . FileHandler ( 'test.log' , encoding = 'utf-8' )
> >> handler . setFormatter ( log . Formatter ( '%(asctime)s %(levelname)s:%(name)s:%(message)s' ))
> >> logger . addHandler ( handler )
> >> logger . setLevel ( 'DEBUG' )
> >> log . basicConfig ()
> >> log . root . handlers [ 0 ]. setLevel ( 'WARNING' )
> >> logger . critical ( 'Running out of disk space.' )
CRITICAL : my_module : Running out of disk space .
> >> print ( open ( 'test.log' ). read ())
2023 - 02 - 07 23 : 21 : 01 , 430 CRITICAL : my_module : Running out of disk space . < list > = dir () # List of local names (variables, funcs, classes, modules).
< dict > = vars () # Dict of local names and their objects. Also locals().
< dict > = globals () # Dict of global names and their objects, e.g. __builtin__. < list > = dir ( < obj > ) # Returns names of object's attributes (including methods).
< dict > = vars ( < obj > ) # Returns dict of writable attributes. Also <obj>.__dict__.
< bool > = hasattr ( < obj > , '<name>' ) # Checks if object possesses attribute with passed name.
value = getattr ( < obj > , '<name>' ) # Returns object's attribute or raises AttributeError.
setattr ( < obj > , '<name>' , value ) # Sets attribute. Only works on objects with __dict__ attr.
delattr ( < obj > , '<name>' ) # Deletes attribute from __dict__. Also `del <obj>.<name>`. < Sig > = inspect . signature ( < func > ) # Returns a Signature object of the passed function.
< dict > = < Sig > . parameters # Returns dict of Parameters. Also <Sig>.return_annotation.
< memb > = < Param > . kind # Returns ParameterKind member (Parameter.KEYWORD_ONLY, …).
< type > = < Param > . annotation # Returns Parameter.empty if missing. Also <Param>.default. Penerjemah CPython hanya dapat menjalankan satu thread dalam satu waktu. Menggunakan banyak thread tidak akan menghasilkan eksekusi yang lebih cepat, kecuali setidaknya salah satu thread berisi operasi I/O.
from threading import Thread , Lock , RLock , Semaphore , Event , Barrier
from concurrent . futures import ThreadPoolExecutor , as_completed < Thread > = Thread ( target = < function > ) # Use `args=<collection>` to set the arguments.
< Thread > . start () # Starts the thread. Also <Thread>.is_alive().
< Thread > . join () # Waits for the thread to finish.'kwargs=<dict>' untuk meneruskan argumen kata kunci ke fungsi.'daemon=True' , atau program tidak akan bisa keluar saat thread masih hidup. < lock > = Lock / RLock () # RLock can only be released by acquirer.
< lock > . acquire () # Waits for the lock to be available.
< lock > . release () # Makes the lock available again. with < lock > : # Enters the block by calling acquire() and
... # exits it with release(), even on error. < Semaphore > = Semaphore ( value = 1 ) # Lock that can be acquired by 'value' threads.
< Event > = Event () # Method wait() blocks until set() is called.
< Barrier > = Barrier ( n_times ) # Wait() blocks until it's called n times. < Queue > = queue . Queue ( maxsize = 0 ) # A thread-safe first-in-first-out queue.
< Queue > . put ( < el > ) # Blocks until queue stops being full.
< Queue > . put_nowait ( < el > ) # Raises queue.Full exception if full.
< el > = < Queue > . get () # Blocks until queue stops being empty.
< el > = < Queue > . get_nowait () # Raises queue.Empty exception if empty. < Exec > = ThreadPoolExecutor ( max_workers = None ) # Or: `with ThreadPoolExecutor() as <name>: ...`
< iter > = < Exec > . map ( < func > , < args_1 > , ...) # Multithreaded and non-lazy map(). Keeps order.
< Futr > = < Exec > . submit ( < func > , < arg_1 > , ...) # Creates a thread and returns its Future obj.
< Exec > . shutdown () # Blocks until all threads finish executing. < bool > = < Future > . done () # Checks if the thread has finished executing.
< obj > = < Future > . result ( timeout = None ) # Waits for thread to finish and returns result.
< bool > = < Future > . cancel () # Cancels or returns False if running/finished.
< iter > = as_completed ( < coll_of_Futures > ) # `next(<iter>)` returns next completed Future.'if __name__ == "__main__": ...' . 'async' dan pemanggilannya dengan 'await' .'asyncio.run(<coroutine>)' untuk memulai coroutine pertama/utama. import asyncio as aio < coro > = < async_function > ( < args > ) # Creates a coroutine by calling async def function.
< obj > = await < coroutine > # Starts the coroutine and returns its result.
< task > = aio . create_task ( < coroutine > ) # Schedules the coroutine for execution.
< obj > = await < task > # Returns coroutine's result. Also <task>.cancel(). < coro > = aio . gather ( < coro / task > , ...) # Schedules coros. Returns list of results on await.
< coro > = aio . wait ( < tasks > , …) # `aio.ALL/FIRST_COMPLETED`. Returns (done, pending).
< iter > = aio . as_completed ( < coros / tasks > ) # Iterator of coros. All return next result on await. import asyncio , collections , curses , curses . textpad , enum , random
P = collections . namedtuple ( 'P' , 'x y' ) # Position
D = enum . Enum ( 'D' , 'n e s w' ) # Direction
W , H = 15 , 7 # Width, Height
def main ( screen ):
curses . curs_set ( 0 ) # Makes cursor invisible.
screen . nodelay ( True ) # Makes getch() non-blocking.
asyncio . run ( main_coroutine ( screen )) # Starts running asyncio code.
async def main_coroutine ( screen ):
moves = asyncio . Queue ()
state = { '*' : P ( 0 , 0 )} | { id_ : P ( W // 2 , H // 2 ) for id_ in range ( 10 )}
ai = [ random_controller ( id_ , moves ) for id_ in range ( 10 )]
mvc = [ human_controller ( screen , moves ), model ( moves , state ), view ( state , screen )]
tasks = [ asyncio . create_task ( coro ) for coro in ai + mvc ]
await asyncio . wait ( tasks , return_when = asyncio . FIRST_COMPLETED )
async def random_controller ( id_ , moves ):
while True :
d = random . choice ( list ( D ))
moves . put_nowait (( id_ , d ))
await asyncio . sleep ( random . triangular ( 0.01 , 0.65 ))
async def human_controller ( screen , moves ):
while True :
key_mappings = { 258 : D . s , 259 : D . n , 260 : D . w , 261 : D . e }
if d := key_mappings . get ( screen . getch ()):
moves . put_nowait (( '*' , d ))
await asyncio . sleep ( 0.005 )
async def model ( moves , state ):
while state [ '*' ] not in ( state [ id_ ] for id_ in range ( 10 )):
id_ , d = await moves . get ()
deltas = { D . n : P ( 0 , - 1 ), D . e : P ( 1 , 0 ), D . s : P ( 0 , 1 ), D . w : P ( - 1 , 0 )}
state [ id_ ] = P (( state [ id_ ]. x + deltas [ d ]. x ) % W , ( state [ id_ ]. y + deltas [ d ]. y ) % H )
async def view ( state , screen ):
offset = P ( curses . COLS // 2 - W // 2 , curses . LINES // 2 - H // 2 )
while True :
screen . erase ()
curses . textpad . rectangle ( screen , offset . y - 1 , offset . x - 1 , offset . y + H , offset . x + W )
for id_ , p in state . items ():
screen . addstr ( offset . y + ( p . y - state [ '*' ]. y + H // 2 ) % H ,
offset . x + ( p . x - state [ '*' ]. x + W // 2 ) % W , str ( id_ ))
screen . refresh ()
await asyncio . sleep ( 0.005 )
if __name__ == '__main__' :
curses . wrapper ( main ) # $ pip3 install tqdm
> >> import tqdm , time
> >> for el in tqdm . tqdm ([ 1 , 2 , 3 ], desc = 'Processing' ):
... time . sleep ( 1 )
Processing : 100 % | ████████████████████ | 3 / 3 [ 00 : 03 < 00 : 00 , 1.00 s / it ] # $ pip3 install matplotlib
import matplotlib . pyplot as plt
plt . plot / bar / scatter ( x_data , y_data [, label = < str > ]) # Also plt.plot(y_data).
plt . legend () # Adds a legend.
plt . title / xlabel / ylabel ( < str > ) # Adds a title or label.
plt . savefig ( < path > ) # Saves the plot.
plt . show () # Displays the plot.
plt . clf () # Clears the plot. # $ pip3 install tabulate
import csv , tabulate
with open ( 'test.csv' , encoding = 'utf-8' , newline = '' ) as file :
rows = list ( csv . reader ( file ))
print ( tabulate . tabulate ( rows , headers = 'firstrow' )) # $ pip3 install windows-curses
import curses , os
from curses import A_REVERSE , KEY_DOWN , KEY_UP , KEY_LEFT , KEY_RIGHT , KEY_ENTER
def main ( screen ):
ch , first , selected , paths = 0 , 0 , 0 , os . listdir ()
while ch != ord ( 'q' ):
height , width = screen . getmaxyx ()
screen . erase ()
for y , filename in enumerate ( paths [ first : first + height ]):
color = A_REVERSE if filename == paths [ selected ] else 0
screen . addnstr ( y , 0 , filename , width - 1 , color )
ch = screen . getch ()
selected += ( ch == KEY_DOWN ) - ( ch == KEY_UP )
selected = max ( 0 , min ( len ( paths ) - 1 , selected ))
first += ( selected >= first + height ) - ( selected < first )
if ch in [ KEY_LEFT , KEY_RIGHT , KEY_ENTER , ord ( ' n ' ), ord ( ' r ' )]:
new_dir = '..' if ch == KEY_LEFT else paths [ selected ]
if os . path . isdir ( new_dir ):
os . chdir ( new_dir )
first , selected , paths = 0 , 0 , os . listdir ()
if __name__ == '__main__' :
curses . wrapper ( main ) # $ pip3 install PySimpleGUI
import PySimpleGUI as sg
text_box = sg . Input ( default_text = '100' , enable_events = True , key = '-QUANTITY-' )
dropdown = sg . InputCombo ([ 'g' , 'kg' , 't' ], 'kg' , readonly = True , enable_events = True , k = '-UNIT-' )
label = sg . Text ( '100 kg is 220.462 lbs.' , key = '-OUTPUT-' )
button = sg . Button ( 'Close' )
window = sg . Window ( 'Weight Converter' , [[ text_box , dropdown ], [ label ], [ button ]])
while True :
event , values = window . read ()
if event in [ sg . WIN_CLOSED , 'Close' ]:
break
try :
quantity = float ( values [ '-QUANTITY-' ])
except ValueError :
continue
unit = values [ '-UNIT-' ]
factors = { 'g' : 0.001 , 'kg' : 1 , 't' : 1000 }
lbs = quantity * factors [ unit ] / 0.45359237
window [ '-OUTPUT-' ]. update ( value = f' { quantity } { unit } is { lbs :g } lbs.' )
window . close () # $ pip3 install requests beautifulsoup4
import requests , bs4 , os
response = requests . get ( 'https://en.wikipedia.org/wiki/Python_(programming_language)' )
document = bs4 . BeautifulSoup ( response . text , 'html.parser' )
table = document . find ( 'table' , class_ = 'infobox vevent' )
python_url = table . find ( 'th' , text = 'Website' ). next_sibling . a [ 'href' ]
logo_url = table . find ( 'img' )[ 'src' ]
logo = requests . get ( f'https: { logo_url } ' ). content
filename = os . path . basename ( logo_url )
with open ( filename , 'wb' ) as file :
file . write ( logo )
print ( f' { python_url } , file:// { os . path . abspath ( filename ) } ' )Perpustakaan untuk menyalin situs web dengan konten dinamis.
# $ pip3 install selenium
from selenium import webdriver
< WebDrv > = webdriver . Chrome / Firefox / Safari / Edge () # Opens a browser. Also <WebDrv>.quit().
< WebDrv > . get ( '<url>' ) # Also <WebDrv>.implicitly_wait(seconds).
< El > = < WebDrv / El > . find_element ( 'css selector' , …) # '<tag>#<id>.<class>[<attr>="<val>"]…'.
< list > = < WebDrv / El > . find_elements ( 'xpath' , …) # '//<tag>[@<attr>="<val>"]…'. See XPath.
< str > = < El > . get_attribute ( < str > ) # Property if exists. Also <El>.text.
< El > . click / clear () # Also <El>.send_keys(<str>). '$x("<xpath>")' : < xpath > = // < element > [ / or // < element > ] # /<child>, //<descendant>, /../<sibling>
< xpath > = // < element > / following :: < element > # Next element. Also preceding/parent/…
< element > = < tag > < conditions > < index > # `<tag> = */a/…`, `<index> = [1/2/…]`.
< condition > = [ < sub_cond > [ and / or < sub_cond > ]] # For negation use `not(<sub_cond>)`.
< sub_cond > = @ < attr > [ = "<val>" ] # `text()=`, `.=` match (complete) text.
< sub_cond > = contains (@ < attr > , "<val>" ) # Is <val> a substring of attr's value?
< sub_cond > = [ // ] < element > # Has matching child? Descendant if //. Flask adalah kerangka/server web mikro. Jika Anda hanya ingin membuka file html di browser web, gunakan 'webbrowser.open(<path>)' sebagai gantinya.
# $ pip3 install flask
import flask as fl app = fl . Flask ( __name__ ) # Returns the app object. Put at the top.
app . run ( host = None , port = None , debug = None ) # Or: $ flask --app FILE run [--ARG[=VAL]]…'http://localhost:5000' . Gunakan 'host="0.0.0.0"' untuk dijalankan secara eksternal. @ app . route ( '/img/<path:filename>' )
def serve_file ( filename ):
return fl . send_from_directory ( 'dirname/' , filename ) @ app . route ( '/<sport>' )
def serve_html ( sport ):
return fl . render_template_string ( '<h1>{{title}}</h1>' , title = sport )'fl.render_template(filename, <kwargs>)' merender file yang terletak di direktori 'template'.'fl.abort(<int>)' mengembalikan kode kesalahan dan 'return fl.redirect(<url>)' mengalihkan.'fl.request.args[<str>]' mengembalikan parameter dari string kueri (URL di sebelah kanan '?').'fl.session[<str>] = <obj>' menyimpan data sesi. Diperlukan kunci rahasia untuk disetel saat startup dengan 'app.secret_key = <str>' . @ app . post ( '/<sport>/odds' )
def serve_json ( sport ):
team = fl . request . form [ 'team' ]
return { 'team' : team , 'odds' : [ 2.09 , 3.74 , 3.68 ]} # $ pip3 install requests
> >> import threading , requests
> >> threading . Thread ( target = app . run , daemon = True ). start ()
> >> url = 'http://localhost:5000/football/odds'
> >> response = requests . post ( url , data = { 'team' : 'arsenal f.c.' })
> >> response . json ()
{ 'team' : 'arsenal f.c.' , 'odds' : [ 2.09 , 3.74 , 3.68 ]} from time import perf_counter
start_time = perf_counter ()
...
duration_in_seconds = perf_counter () - start_time > >> from timeit import timeit
> >> timeit ( 'list(range(10000))' , number = 1000 , globals = globals (), setup = 'pass' )
0.19373 $ pip3 install line_profiler
$ echo '@profile
def main():
a = list(range(10000))
b = set(range(10000))
main()' > test.py
$ kernprof -lv test.py
Line # Hits Time Per Hit % Time Line Contents
==============================================================
1 @profile
2 def main():
3 1 253.4 253.4 32.2 a = list(range(10000))
4 1 534.1 534.1 67.8 b = set(range(10000))
$ apt/brew install graphviz && pip3 install gprof2dot snakeviz # Or download installer.
$ tail --lines=+2 test.py > test.py # Removes first line.
$ python3 -m cProfile -o test.prof test.py # Runs built-in profiler.
$ gprof2dot --format=pstats test.prof | dot -T png -o test.png # Generates call graph.
$ xdg-open/open test.png # Displays call graph.
$ snakeviz test.prof # Displays flame graph. +--------------+------------+-------------------------------+-------+------+
| pip3 install | Target | How to run | Lines | Live |
+--------------+------------+-------------------------------+-------+------+
| pyinstrument | CPU | pyinstrument test.py | No | No |
| py-spy | CPU | py-spy top -- python3 test.py | No | Yes |
| scalene | CPU+Memory | scalene test.py | Yes | No |
| memray | Memory | memray run --live test.py | Yes | Yes |
+--------------+------------+-------------------------------+-------+------+
Bahasa mini manipulasi array. Ini dapat berjalan hingga seratus kali lebih cepat daripada kode Python yang setara. Alternatif yang lebih cepat lagi yang berjalan pada GPU disebut CuPy.
# $ pip3 install numpy
import numpy as np < array > = np . array ( < list / list_of_lists / … > ) # Returns a 1d/2d/… NumPy array.
< array > = np . zeros / ones / empty ( < shape > ) # Also np.full(<shape>, <el>).
< array > = np . arange ( from_inc , to_exc , ± step ) # Also np.linspace(start, stop, len).
< array > = np . random . randint ( from_inc , to_exc , < shape > ) # Also np.random.random(<shape>). < view > = < array > . reshape ( < shape > ) # Also `<array>.shape = <shape>`.
< array > = < array > . flatten () # Also `<view> = <array>.ravel()`.
< view > = < array > . transpose () # Or: <array>.T < array > = np . copy / abs / sqrt / log / int64 ( < array > ) # Returns new array of the same shape.
< array > = < array > . sum / max / mean / argmax / all ( axis ) # Aggregates specified dimension.
< array > = np . apply_along_axis ( < func > , axis , < array > ) # Func can return a scalar or array. < array > = np . concatenate ( < list_of_arrays > , axis = 0 ) # Links arrays along first axis (rows).
< array > = np . vstack / column_stack ( < list_of_arrays > ) # Treats 1d arrays as rows or columns.
< array > = np . tile / repeat ( < array > , < int / list > [, axis ]) # Tiles array or repeats its elements.<el> = <2d>[row_index, col_index] # Or: <3d>[<int>, <int>, <int>]
<1d_view> = <2d>[row_index] # Or: <3d>[<int>, <int>, <slice>]
<1d_view> = <2d>[:, col_index] # Or: <3d>[<int>, <slice>, <int>]
<2d_view> = <2d>[from:to_row_i, from:to_col_i] # Or: <3d>[<int>, <slice>, <slice>] <1d_array> = <2d>[row_indices, col_indices] # Or: <3d>[<int/1d>, <1d>, <1d>]
<2d_array> = <2d>[row_indices] # Or: <3d>[<int/1d>, <1d>, <slice>]
<2d_array> = <2d>[:, col_indices] # Or: <3d>[<int/1d>, <slice>, <1d>]
<2d_array> = <2d>[np.ix_(row_indices, col_indices)] # Or: <3d>[<int/1d/2d>, <2d>, <2d>] <2d_bools> = <2d> > <el/1d/2d> # 1d object must have size of a row.
<1/2d_arr> = <2d>[<2d/1d_bools>] # 1d_bools must have size of a column.':' mengembalikan sepotong indeks semua dimensi. Dimensi yang dihilangkan secara default adalah ':' .'obj[i, j]' menjadi 'obj[(i, j)]' !'ix_([1, 2], [3, 4])' mengembalikan '[[1], [2]]' dan '[[3, 4]]' . Karena aturan penyiaran, ini sama dengan menggunakan '[[1, 1], [2, 2]]' dan '[[3, 4], [3, 4]]' .Seperangkat aturan yang digunakan fungsi NumPy untuk beroperasi pada array dengan bentuk berbeda.
left = [ 0.1 , 0.6 , 0.8 ] # Shape: (3,)
right = [[ 0.1 ], [ 0.6 ], [ 0.8 ]] # Shape: (3, 1) left = [[ 0.1 , 0.6 , 0.8 ]] # Shape: (1, 3) <- !
right = [[ 0.1 ], [ 0.6 ], [ 0.8 ]] # Shape: (3, 1) left = [[ 0.1 , 0.6 , 0.8 ], # Shape: (3, 3) <- !
[ 0.1 , 0.6 , 0.8 ],
[ 0.1 , 0.6 , 0.8 ]]
right = [[ 0.1 , 0.1 , 0.1 ], # Shape: (3, 3) <- !
[ 0.6 , 0.6 , 0.6 ],
[ 0.8 , 0.8 , 0.8 ]][0.1, 0.6, 0.8] => [1, 2, 1] ): > >> points = np . array ([ 0.1 , 0.6 , 0.8 ])
[ 0.1 , 0.6 , 0.8 ]
> >> wrapped_points = points . reshape ( 3 , 1 )
[[ 0.1 ], [ 0.6 ], [ 0.8 ]]
> >> distances = points - wrapped_points
[[ 0. , 0.5 , 0.7 ],
[ - 0.5 , 0. , 0.2 ],
[ - 0.7 , - 0.2 , 0. ]]
> >> distances = np . abs ( distances )
[[ 0. , 0.5 , 0.7 ],
[ 0.5 , 0. , 0.2 ],
[ 0.7 , 0.2 , 0. ]]
> >> distances [ range ( 3 ), range ( 3 )] = np . inf
[[ inf , 0.5 , 0.7 ],
[ 0.5 , inf , 0.2 ],
[ 0.7 , 0.2 , inf ]]
> >> distances . argmin ( 1 )
[ 1 , 2 , 1 ] # $ pip3 install pillow
from PIL import Image < Image > = Image . new ( '<mode>' , ( width , height )) # Creates new image. Also `color=<int/tuple>`.
< Image > = Image . open ( < path > ) # Identifies format based on file's contents.
< Image > = < Image > . convert ( '<mode>' ) # Converts image to the new mode (see Modes).
< Image > . save ( < path > ) # Selects format based on extension (PNG/JPG…).
< Image > . show () # Displays image in default preview app. < int / tup > = < Image > . getpixel (( x , y )) # Returns pixel's value (its color).
< ImgCore > = < Image > . getdata () # Returns a flattened view of pixel values.
< Image > . putpixel (( x , y ), < int / tuple > ) # Updates pixel's value. Clips passed int/s.
< Image > . putdata ( < list / ImgCore > ) # Updates pixels with a copy of the sequence.
< Image > . paste ( < Image > , ( x , y )) # Draws passed image at the specified location. < Image > = < Image > . filter ( < Filter > ) # Use ImageFilter.<name>(<args>) for Filter.
< Image > = < Enhance > . enhance ( < float > ) # Use ImageEnhance.<name>(<Image>) for Enhance. < array > = np . array ( < Image > ) # Creates a 2d/3d NumPy array from the image.
< Image > = Image . fromarray ( np . uint8 ( < array > )) # Use <array>.clip(0, 255) to clip the values.'L' - Ringan (gambar skala abu-abu). Setiap piksel adalah int antara 0 dan 255.'RGB' - Merah, hijau, biru (gambar berwarna asli). Setiap piksel adalah tupel dari tiga int.'RGBA' - RGB dengan alfa. Alfa rendah (yaitu int) membuat piksel lebih transparan.'HSV' - Rona, saturasi, nilai. Tiga int mewakili warna dalam ruang warna HSV. WIDTH , HEIGHT = 100 , 100
n_pixels = WIDTH * HEIGHT
hues = ( 255 * i / n_pixels for i in range ( n_pixels ))
img = Image . new ( 'HSV' , ( WIDTH , HEIGHT ))
img . putdata ([( int ( h ), 255 , 255 ) for h in hues ])
img . convert ( 'RGB' ). save ( 'test.png' ) from random import randint
add_noise = lambda value : max ( 0 , min ( 255 , value + randint ( - 20 , 20 )))
img = Image . open ( 'test.png' ). convert ( 'HSV' )
img . putdata ([( add_noise ( h ), s , v ) for h , s , v in img . getdata ()])
img . show () from PIL import ImageDraw
< Draw > = ImageDraw . Draw ( < Image > ) # Object for adding 2D graphics to the image.
< Draw > . point (( x , y )) # Draws a point. Truncates floats into ints.
< Draw > . line (( x1 , y1 , x2 , y2 [, ...])) # To get anti-aliasing use Image's resize().
< Draw > . arc (( x1 , y1 , x2 , y2 ), deg1 , deg2 ) # Draws in clockwise dir. Also pieslice().
< Draw > . rectangle (( x1 , y1 , x2 , y2 )) # Also rounded_rectangle(), regular_polygon().
< Draw > . polygon (( x1 , y1 , x2 , y2 , ...)) # Last point gets connected to the first.
< Draw > . ellipse (( x1 , y1 , x2 , y2 )) # To rotate use Image's rotate() and paste().
< Draw > . text (( x , y ), < str > , font = < Font > ) # `<Font> = ImageFont.truetype(<path>, size)`.'fill=<color>' untuk mengatur warna utama.'width=<int>' untuk mengatur lebar garis atau kontur.'outline=<color>' untuk mengatur warna kontur.'#rrggbb[aa]' atau nama warna. # $ pip3 install imageio
from PIL import Image , ImageDraw
import imageio
WIDTH , HEIGHT , R = 126 , 126 , 10
frames = []
for velocity in range ( 1 , 16 ):
y = sum ( range ( velocity ))
frame = Image . new ( 'L' , ( WIDTH , HEIGHT ))
draw = ImageDraw . Draw ( frame )
draw . ellipse (( WIDTH / 2 - R , y , WIDTH / 2 + R , y + R * 2 ), fill = 'white' )
frames . append ( frame )
frames += reversed ( frames [ 1 : - 1 ])
imageio . mimsave ( 'test.gif' , frames , duration = 0.03 ) import wave < Wave > = wave . open ( '<path>' ) # Opens the WAV file for reading.
< int > = < Wave > . getframerate () # Returns number of frames per second.
< int > = < Wave > . getnchannels () # Returns number of samples per frame.
< int > = < Wave > . getsampwidth () # Returns number of bytes per sample.
< tuple > = < Wave > . getparams () # Returns namedtuple of all parameters.
< bytes > = < Wave > . readframes ( nframes ) # Returns next n frames (-1 returns all). < Wave > = wave . open ( '<path>' , 'wb' ) # Creates/truncates a file for writing.
< Wave > . setframerate ( < int > ) # Pass 44100 for CD, 48000 for video.
< Wave > . setnchannels ( < int > ) # Pass 1 for mono, 2 for stereo.
< Wave > . setsampwidth ( < int > ) # Pass 2 for CD, 3 for hi-res sound.
< Wave > . setparams ( < tuple > ) # Tuple must contain all parameters.
< Wave > . writeframes ( < bytes > ) # Appends frames to the file. +-----------+-----------+------+-----------+
| sampwidth | min | zero | max |
+-----------+-----------+------+-----------+
| 1 | 0 | 128 | 255 |
| 2 | -32768 | 0 | 32767 |
| 3 | -8388608 | 0 | 8388607 |
+-----------+-----------+------+-----------+
def read_wav_file ( filename ):
def get_int ( bytes_obj ):
an_int = int . from_bytes ( bytes_obj , 'little' , signed = ( p . sampwidth != 1 ))
return an_int - 128 * ( p . sampwidth == 1 )
with wave . open ( filename ) as file :
p = file . getparams ()
frames = file . readframes ( - 1 )
bytes_samples = ( frames [ i : i + p . sampwidth ] for i in range ( 0 , len ( frames ), p . sampwidth ))
return [ get_int ( b ) / pow ( 2 , ( p . sampwidth * 8 ) - 1 ) for b in bytes_samples ], p def write_to_wav_file ( filename , samples_f , p = None , nchannels = 1 , sampwidth = 2 , framerate = 44100 ):
def get_bytes ( a_float ):
a_float = max ( - 1 , min ( 1 - 2e-16 , a_float ))
a_float += p . sampwidth == 1
a_float *= pow ( 2 , ( p . sampwidth * 8 ) - 1 )
return int ( a_float ). to_bytes ( p . sampwidth , 'little' , signed = ( p . sampwidth != 1 ))
if p is None :
p = wave . _wave_params ( nchannels , sampwidth , framerate , 0 , 'NONE' , 'not compressed' )
with wave . open ( filename , 'wb' ) as file :
file . setparams ( p )
file . writeframes ( b'' . join ( get_bytes ( f ) for f in samples_f )) from math import pi , sin
samples_f = ( sin ( i * 2 * pi * 440 / 44100 ) for i in range ( 100_000 ))
write_to_wav_file ( 'test.wav' , samples_f ) from random import uniform
samples_f , params = read_wav_file ( 'test.wav' )
samples_f = ( f + uniform ( - 0.05 , 0.05 ) for f in samples_f )
write_to_wav_file ( 'test.wav' , samples_f , params ) # $ pip3 install simpleaudio
from simpleaudio import play_buffer
with wave . open ( 'test.wav' ) as file :
p = file . getparams ()
frames = file . readframes ( - 1 )
play_buffer ( frames , p . nchannels , p . sampwidth , p . framerate ). wait_done () # $ pip3 install pyttsx3
import pyttsx3
engine = pyttsx3 . init ()
engine . say ( 'Sally sells seashells by the seashore.' )
engine . runAndWait () # $ pip3 install simpleaudio
import array , itertools as it , math , simpleaudio
F = 44100
P1 = '71♩,69♪,,71♩,66♪,,62♩,66♪,,59♩,,,71♩,69♪,,71♩,66♪,,62♩,66♪,,59♩,,,'
P2 = '71♩,73♪,,74♩,73♪,,74♪,,71♪,,73♩,71♪,,73♪,,69♪,,71♩,69♪,,71♪,,67♪,,71♩,,,'
get_pause = lambda seconds : it . repeat ( 0 , int ( seconds * F ))
sin_f = lambda i , hz : math . sin ( i * 2 * math . pi * hz / F )
get_wave = lambda hz , seconds : ( sin_f ( i , hz ) for i in range ( int ( seconds * F )))
get_hz = lambda note : 440 * 2 ** (( int ( note [: 2 ]) - 69 ) / 12 )
get_sec = lambda note : 1 / 4 if '♩' in note else 1 / 8
get_samples = lambda note : get_wave ( get_hz ( note ), get_sec ( note )) if note else get_pause ( 1 / 8 )
samples_f = it . chain . from_iterable ( get_samples ( n ) for n in ( P1 + P2 ). split ( ',' ))
samples_i = array . array ( 'h' , ( int ( f * 30000 ) for f in samples_f ))
simpleaudio . play_buffer ( samples_i , 1 , 2 , F ). wait_done () # $ pip3 install pygame
import pygame as pg
pg . init ()
screen = pg . display . set_mode (( 500 , 500 ))
rect = pg . Rect ( 240 , 240 , 20 , 20 )
while not pg . event . get ( pg . QUIT ):
deltas = { pg . K_UP : ( 0 , - 20 ), pg . K_RIGHT : ( 20 , 0 ), pg . K_DOWN : ( 0 , 20 ), pg . K_LEFT : ( - 20 , 0 )}
for event in pg . event . get ( pg . KEYDOWN ):
dx , dy = deltas . get ( event . key , ( 0 , 0 ))
rect = rect . move (( dx , dy ))
screen . fill ( pg . Color ( 'black' ))
pg . draw . rect ( screen , pg . Color ( 'white' ), rect )
pg . display . flip ()Objek untuk menyimpan koordinat persegi panjang.
< Rect > = pg . Rect ( x , y , width , height ) # Creates Rect object. Truncates passed floats.
< int > = < Rect > . x / y / centerx / centery / … # Top, right, bottom, left. Allows assignments.
< tup . > = < Rect > . topleft / center / … # Topright, bottomright, bottomleft. Same.
< Rect > = < Rect > . move (( delta_x , delta_y )) # Use move_ip() to move in-place. < bool > = < Rect > . collidepoint (( x , y )) # Checks if rectangle contains the point.
< bool > = < Rect > . colliderect ( < Rect > ) # Checks if the two rectangles overlap.
< int > = < Rect > . collidelist ( < list_of_Rect > ) # Returns index of first colliding Rect or -1.
< list > = < Rect > . collidelistall ( < list_of_Rect > ) # Returns indices of all colliding rectangles.Objek untuk merepresentasikan gambar.
< Surf > = pg . display . set_mode (( width , height )) # Opens new window and returns its surface.
< Surf > = pg . Surface (( width , height )) # New RGB surface. RGBA if `flags=pg.SRCALPHA`.
< Surf > = pg . image . load ( < path / file > ) # Loads the image. Format depends on source.
< Surf > = pg . surfarray . make_surface ( < np_array > ) # Also `<np_arr> = surfarray.pixels3d(<Surf>)`.
< Surf > = < Surf > . subsurface ( < Rect > ) # Creates a new surface from the cutout. < Surf > . fill ( color ) # Tuple, Color('#rrggbb[aa]') or Color(<name>).
< Surf > . set_at (( x , y ), color ) # Updates pixel. Also <Surf>.get_at((x, y)).
< Surf > . blit ( < Surf > , ( x , y )) # Draws passed surface at specified location. from pygame . transform import scale , ...
< Surf > = scale ( < Surf > , ( width , height )) # Returns scaled surface.
< Surf > = rotate ( < Surf > , anticlock_degrees ) # Returns rotated and scaled surface.
< Surf > = flip ( < Surf > , x_bool , y_bool ) # Returns flipped surface. from pygame . draw import line , ...
line ( < Surf > , color , ( x1 , y1 ), ( x2 , y2 ), width ) # Draws a line to the surface.
arc ( < Surf > , color , < Rect > , from_rad , to_rad ) # Also ellipse(<Surf>, color, <Rect>, width=0).
rect ( < Surf > , color , < Rect > , width = 0 ) # Also polygon(<Surf>, color, points, width=0). < Font > = pg . font . Font ( < path / file > , size ) # Loads TTF file. Pass None for default font.
< Surf > = < Font > . render ( text , antialias , color ) # Background color can be specified at the end. < Sound > = pg . mixer . Sound ( < path / file / bytes > ) # WAV file or bytes/array of signed shorts.
< Sound > . play / stop () # Also set_volume(<float>), fadeout(msec). import collections , dataclasses , enum , io , itertools as it , pygame as pg , urllib . request
from random import randint
P = collections . namedtuple ( 'P' , 'x y' ) # Position
D = enum . Enum ( 'D' , 'n e s w' ) # Direction
W , H , MAX_S = 50 , 50 , P ( 5 , 10 ) # Width, Height, Max speed
def main ():
def get_screen ():
pg . init ()
return pg . display . set_mode (( W * 16 , H * 16 ))
def get_images ():
url = 'https://gto76.github.io/python-cheatsheet/web/mario_bros.png'
img = pg . image . load ( io . BytesIO ( urllib . request . urlopen ( url ). read ()))
return [ img . subsurface ( get_rect ( x , 0 )) for x in range ( img . get_width () // 16 )]
def get_mario ():
Mario = dataclasses . make_dataclass ( 'Mario' , 'rect spd facing_left frame_cycle' . split ())
return Mario ( get_rect ( 1 , 1 ), P ( 0 , 0 ), False , it . cycle ( range ( 3 )))
def get_tiles ():
border = [( x , y ) for x in range ( W ) for y in range ( H ) if x in [ 0 , W - 1 ] or y in [ 0 , H - 1 ]]
platforms = [( randint ( 1 , W - 2 ), randint ( 2 , H - 2 )) for _ in range ( W * H // 10 )]
return [ get_rect ( x , y ) for x , y in border + platforms ]
def get_rect ( x , y ):
return pg . Rect ( x * 16 , y * 16 , 16 , 16 )
run ( get_screen (), get_images (), get_mario (), get_tiles ())
def run ( screen , images , mario , tiles ):
clock = pg . time . Clock ()
pressed = set ()
while not pg . event . get ( pg . QUIT ) and clock . tick ( 28 ):
keys = { pg . K_UP : D . n , pg . K_RIGHT : D . e , pg . K_DOWN : D . s , pg . K_LEFT : D . w }
pressed |= { keys . get ( e . key ) for e in pg . event . get ( pg . KEYDOWN )}
pressed -= { keys . get ( e . key ) for e in pg . event . get ( pg . KEYUP )}
update_speed ( mario , tiles , pressed )
update_position ( mario , tiles )
draw ( screen , images , mario , tiles )
def update_speed ( mario , tiles , pressed ):
x , y = mario . spd
x += 2 * (( D . e in pressed ) - ( D . w in pressed ))
x += ( x < 0 ) - ( x > 0 )
y += 1 if D . s not in get_boundaries ( mario . rect , tiles ) else ( D . n in pressed ) * - 10
mario . spd = P ( x = max ( - MAX_S . x , min ( MAX_S . x , x )), y = max ( - MAX_S . y , min ( MAX_S . y , y )))
def update_position ( mario , tiles ):
x , y = mario . rect . topleft
n_steps = max ( abs ( s ) for s in mario . spd )
for _ in range ( n_steps ):
mario . spd = stop_on_collision ( mario . spd , get_boundaries ( mario . rect , tiles ))
x , y = x + ( mario . spd . x / n_steps ), y + ( mario . spd . y / n_steps )
mario . rect . topleft = x , y
def get_boundaries ( rect , tiles ):
deltas = { D . n : P ( 0 , - 1 ), D . e : P ( 1 , 0 ), D . s : P ( 0 , 1 ), D . w : P ( - 1 , 0 )}
return { d for d , delta in deltas . items () if rect . move ( delta ). collidelist ( tiles ) != - 1 }
def stop_on_collision ( spd , bounds ):
return P ( x = 0 if ( D . w in bounds and spd . x < 0 ) or ( D . e in bounds and spd . x > 0 ) else spd . x ,
y = 0 if ( D . n in bounds and spd . y < 0 ) or ( D . s in bounds and spd . y > 0 ) else spd . y )
def draw ( screen , images , mario , tiles ):
screen . fill (( 85 , 168 , 255 ))
mario . facing_left = mario . spd . x < 0 if mario . spd . x else mario . facing_left
is_airborne = D . s not in get_boundaries ( mario . rect , tiles )
image_index = 4 if is_airborne else ( next ( mario . frame_cycle ) if mario . spd . x else 6 )
screen . blit ( images [ image_index + ( mario . facing_left * 9 )], mario . rect )
for t in tiles :
is_border = t . x in [ 0 , ( W - 1 ) * 16 ] or t . y in [ 0 , ( H - 1 ) * 16 ]
screen . blit ( images [ 18 if is_border else 19 ], t )
pg . display . flip ()
if __name__ == '__main__' :
main ()Perpustakaan analisis data. Sebagai contoh, lihat Plotly.
# $ pip3 install pandas matplotlib
import pandas as pd , matplotlib . pyplot as pltKamus yang dipesan dengan nama.
> >> s = pd . Series ([ 1 , 2 ], index = [ 'x' , 'y' ], name = 'a' ); s
x 1
y 2
Name : a , dtype : int64 < S > = pd . Series ( < list > ) # Uses list's indices for 'index'.
< S > = pd . Series ( < dict > ) # Uses dictionary's keys for 'index'. < el > = < S > . loc [ key ] # Or: <S>.iloc[i]
< S > = < S > . loc [ coll_of_keys ] # Or: <S>.iloc[coll_of_i]
< S > = < S > . loc [ from_key : to_key_inc ] # Or: <S>.iloc[from_i : to_i_exc] < el > = < S > [ key / i ] # Or: <S>.<key>
< S > = < S > [ coll_of_keys / coll_of_i ] # Or: <S>[key/i : key/i]
< S > = < S > [ bools ] # Or: <S>.loc/iloc[bools] < S > = < S > > < el / S > # Returns S of bools. Pairs items by keys.
< S > = < S > + < el / S > # Items with non-matching keys get value NaN. < S > = pd . concat ( < coll_of_S > ) # Concats multiple series into one long Series.
< S > = < S > . combine_first ( < S > ) # Adds items that are not yet present.
< S > . update ( < S > ) # Updates items that are already present. < S > . plot . line / area / bar / pie / hist () # Generates a plot. `plt.show()` displays it.'obj[x, y]' diubah menjadi 'obj[(x, y)]' !'np.int64' . Seri diubah menjadi 'float64' jika kita menetapkan np.nan ke item mana pun. Gunakan '<S>.astype(<str/type>)' untuk mendapatkan Seri yang dikonversi.'pd.Series([100], dtype="int8") + 100' . < el > = < S > . sum / max / mean / idxmax / all () # Or: <S>.agg(lambda <S>: <el>)
< S > = < S > . rank / diff / cumsum / ffill / interpol …() # Or: <S>.agg/transform(lambda <S>: <S>)
< S > = < S > . isna / fillna / isin ([ < el / coll > ]) # Or: <S>.agg/transform/map(lambda <el>: <el>) +--------------+-------------+-------------+---------------+
| | 'sum' | ['sum'] | {'s': 'sum'} |
+--------------+-------------+-------------+---------------+
| s.apply(…) | 3 | sum 3 | s 3 |
| s.agg(…) | | | |
+--------------+-------------+-------------+---------------+
+--------------+-------------+-------------+---------------+
| | 'rank' | ['rank'] | {'r': 'rank'} |
+--------------+-------------+-------------+---------------+
| s.apply(…) | | rank | |
| s.agg(…) | x 1.0 | x 1.0 | r x 1.0 |
| | y 2.0 | y 2.0 | y 2.0 |
+--------------+-------------+-------------+---------------+
'inplace=True' .'<S>[key_1, key_2]' untuk mendapatkan nilainya.Tabel dengan baris dan kolom berlabel.
> >> df = pd . DataFrame ([[ 1 , 2 ], [ 3 , 4 ]], index = [ 'a' , 'b' ], columns = [ 'x' , 'y' ]); df
x y
a 1 2
b 3 4 < DF > = pd . DataFrame ( < list_of_rows > ) # Rows can be either lists, dicts or series.
< DF > = pd . DataFrame ( < dict_of_columns > ) # Columns can be either lists, dicts or series. < el > = < DF > . loc [ row_key , col_key ] # Or: <DF>.iloc[row_i, col_i]
< S / DF > = < DF > . loc [ row_key / s ] # Or: <DF>.iloc[row_i/s]
< S / DF > = < DF > . loc [:, col_key / s ] # Or: <DF>.iloc[:, col_i/s]
< DF > = < DF > . loc [ row_bools , col_bools ] # Or: <DF>.iloc[row_bools, col_bools] < S / DF > = < DF > [ col_key / s ] # Or: <DF>.<col_key>
< DF > = < DF > [ < S_of_bools > ] # Filters rows. For example `df[df.x > 1]`.
< DF > = < DF > [ < DF_of_bools > ] # Assigns NaN to items that are False in bools. < DF > = < DF > > < el / S / DF > # Returns DF of bools. S is treated as a row.
< DF > = < DF > + < el / S / DF > # Items with non-matching keys get value NaN. < DF > = < DF > . set_index ( col_key ) # Replaces row keys with column's values.
< DF > = < DF > . reset_index ( drop = False ) # Drops or moves row keys to column named index.
< DF > = < DF > . sort_index ( ascending = True ) # Sorts rows by row keys. Use `axis=1` for cols.
< DF > = < DF > . sort_values ( col_key / s ) # Sorts rows by passed column/s. Also `axis=1`. < DF > = < DF > . head / tail / sample ( < int > ) # Returns first, last, or random n rows.
< DF > = < DF > . describe () # Describes columns. Also info(), corr(), shape.
< DF > = < DF > . query ( '<query>' ) # Filters rows. For example `df.query('x > 1')`. < DF > . plot . line / area / bar / scatter ( x = col_key , …) # `y=col_key/s`. Also hist/box(by=col_key).
plt . show () # Displays the plot. Also plt.savefig(<path>). > >> df_2 = pd . DataFrame ([[ 4 , 5 ], [ 6 , 7 ]], index = [ 'b' , 'c' ], columns = [ 'y' , 'z' ]); df_2
y z
b 4 5
c 6 7 +-----------------------+---------------+------------+------------+---------------------------+
| | 'outer' | 'inner' | 'left' | Description |
+-----------------------+---------------+------------+------------+---------------------------+
| df.merge(df_2, | x y z | x y z | x y z | Merges on column if 'on' |
| on='y', | 0 1 2 . | 3 4 5 | 1 2 . | or 'left_on/right_on' are |
| how=…) | 1 3 4 5 | | 3 4 5 | set, else on shared cols. |
| | 2 . 6 7 | | | Uses 'inner' by default. |
+-----------------------+---------------+------------+------------+---------------------------+
| df.join(df_2, | x yl yr z | | x yl yr z | Merges on row keys. |
| lsuffix='l', | a 1 2 . . | x yl yr z | 1 2 . . | Uses 'left' by default. |
| rsuffix='r', | b 3 4 4 5 | 3 4 4 5 | 3 4 4 5 | If Series is passed, it |
| how=…) | c . . 6 7 | | | is treated as a column. |
+-----------------------+---------------+------------+------------+---------------------------+
| pd.concat([df, df_2], | x y z | y | | Adds rows at the bottom. |
| axis=0, | a 1 2 . | 2 | | Uses 'outer' by default. |
| join=…) | b 3 4 . | 4 | | A Series is treated as a |
| | b . 4 5 | 4 | | column. To add a row use |
| | c . 6 7 | 6 | | pd.concat([df, DF([s])]). |
+-----------------------+---------------+------------+------------+---------------------------+
| pd.concat([df, df_2], | x y y z | | | Adds columns at the |
| axis=1, | a 1 2 . . | x y y z | | right end. Uses 'outer' |
| join=…) | b 3 4 4 5 | 3 4 4 5 | | by default. A Series is |
| | c . . 6 7 | | | treated as a column. |
+-----------------------+---------------+------------+------------+---------------------------+
< S > = < DF > . sum / max / mean / idxmax / all () # Or: <DF>.apply/agg(lambda <S>: <el>)
< DF > = < DF > . rank / diff / cumsum / ffill / interpo …() # Or: <DF>.apply/agg/transform(lambda <S>: <S>)
< DF > = < DF > . isna / fillna / isin ([ < el / coll > ]) # Or: <DF>.applymap(lambda <el>: <el>) +-----------------+---------------+---------------+---------------+
| | 'sum' | ['sum'] | {'x': 'sum'} |
+-----------------+---------------+---------------+---------------+
| df.apply(…) | x 4 | x y | x 4 |
| df.agg(…) | y 6 | sum 4 6 | |
+-----------------+---------------+---------------+---------------+
+-----------------+---------------+---------------+---------------+
| | 'rank' | ['rank'] | {'x': 'rank'} |
+-----------------+---------------+---------------+---------------+
| df.apply(…) | | x y | |
| df.agg(…) | x y | rank rank | x |
| df.transform(…) | a 1.0 1.0 | a 1.0 1.0 | a 1.0 |
| | b 2.0 2.0 | b 2.0 2.0 | b 2.0 |
+-----------------+---------------+---------------+---------------+
'axis=1' untuk memproses baris.'<DF>.loc[row_key, (col_key_1, col_key_2)]' . < DF > = < DF > . xs ( row_key , level = < int > ) # Rows with key on passed level of multi-index.
< DF > = < DF > . xs ( row_keys , level = < ints > ) # Rows that have first key on first level, etc.
< DF > = < DF > . set_index ( col_keys ) # Combines multiple columns into a multi-index.
< S / DF > = < DF > . stack / unstack ( level = - 1 ) # Combines col keys with row keys or vice versa.
< DF > = < DF > . pivot_table ( index = col_key / s ) # `columns=key/s, values=key/s, aggfunc='mean'`. < DF > = pd . read_json / html ( '<str/path/url>' ) # Run `$ pip3 install beautifulsoup4 lxml`.
< DF > = pd . read_csv ( '<path/url>' ) # `header/index_col/dtype/usecols/…=<obj>`.
< DF > = pd . read_pickle / excel ( '<path/url>' ) # Use `sheet_name=None` to get all Excel sheets.
< DF > = pd . read_sql ( '<table/query>' , < conn . > ) # SQLite3/SQLAlchemy connection (see #SQLite). < dict > = < DF > . to_dict ( 'd/l/s/…' ) # Returns columns as dicts, lists or series.
< str > = < DF > . to_json / html / csv / latex () # Saves output to a file if path is passed.
< DF > . to_pickle / excel ( < path > ) # Run `$ pip3 install "pandas[excel]" odfpy`.
< DF > . to_sql ( '<table_name>' , < connection > ) # Also `if_exists='fail/replace/append'`.'<S> = pd.to_datetime(<S>, errors="coerce")' , yang menggunakan PD.nat.'<S>.dt.year/date/…' .Objek yang dikelompokkan bersama -sama baris DataFrame berdasarkan nilai kolom yang ditularkan.
< GB > = < DF > . groupby ( col_key / s ) # Splits DF into groups based on passed column.
< DF > = < GB > . apply ( < func > ) # Maps each group. Func can return DF, S or el.
< DF > = < GB > . filter ( < func > ) # Drops a group if function returns False.
< DF > = < GB > . get_group ( < el > ) # Selects a group by grouping column's value.
< S > = < GB > . size () # S of group sizes. Same keys as get_group().
< GB > = < GB > [ col_key ] # Single column GB. All operations return S. < DF > = < GB > . sum / max / mean / idxmax / all () # Or: <GB>.agg(lambda <S>: <el>)
< DF > = < GB > . rank / diff / cumsum / ffill () # Or: <GB>.transform(lambda <S>: <S>)
< DF > = < GB > . fillna ( < el > ) # Or: <GB>.transform(lambda <S>: <S>) 'z' di reset_index (): > >> df = pd . DataFrame ([[ 1 , 2 , 3 ], [ 4 , 5 , 6 ], [ 7 , 8 , 6 ]], list ( 'abc' ), list ( 'xyz' ))
> >> gb = df . groupby ( 'z' ); gb . apply ( print )
x y z
a 1 2 3
x y z
b 4 5 6
c 7 8 6
>> > gb . sum ()
x y
z
3 1 2
6 11 13Objek untuk perhitungan jendela bergulir.
< RS / RDF / RGB > = < S / DF / GB > . rolling ( win_size ) # Also: `min_periods=None, center=False`.
< RS / RDF / RGB > = < RDF / RGB > [ col_key / s ] # Or: <RDF/RGB>.col_key
< S / DF > = < R > . mean / sum / max () # Or: <R>.apply/agg(<agg_func/str>) # $ pip3 install plotly kaleido pandas
import plotly . express as px , pandas as pd < Fig > = px . line ( < DF > , x = col_key , y = col_key ) # Or: px.line(x=<list>, y=<list>)
< Fig > . update_layout ( margin = dict ( t = 0 , r = 0 , b = 0 , l = 0 )) # Also `paper_bgcolor='rgb(0, 0, 0)'`.
< Fig > . write_html / json / image ( '<path>' ) # <Fig>.show() displays the plot. < Fig > = px . area / bar / box ( < DF > , x = col_key , y = col_key ) # Also `color=col_key`.
< Fig > = px . scatter ( < DF > , x = col_key , y = col_key ) # Also `color/size/symbol=col_key`.
< Fig > = px . scatter_3d ( < DF > , x = col_key , y = col_key , …) # `z=col_key`. Also color/size/symbol.
< Fig > = px . histogram ( < DF > , x = col_key [, nbins = < int > ]) # Number of bins depends on DF size. 
covid = pd . read_csv ( 'https://raw.githubusercontent.com/owid/covid-19-data/8dde8ca49b'
'6e648c17dd420b2726ca0779402651/public/data/owid-covid-data.csv' ,
usecols = [ 'iso_code' , 'date' , 'total_deaths' , 'population' ])
continents = pd . read_csv ( 'https://gto76.github.io/python-cheatsheet/web/continents.csv' ,
usecols = [ 'Three_Letter_Country_Code' , 'Continent_Name' ])
df = pd . merge ( covid , continents , left_on = 'iso_code' , right_on = 'Three_Letter_Country_Code' )
df = df . groupby ([ 'Continent_Name' , 'date' ]). sum (). reset_index ()
df [ 'Total Deaths per Million' ] = df . total_deaths * 1e6 / df . population
df = df [ df . date > '2020-03-14' ]
df = df . rename ({ 'date' : 'Date' , 'Continent_Name' : 'Continent' }, axis = 'columns' )
px . line ( df , x = 'Date' , y = 'Total Deaths per Million' , color = 'Continent' ). show ()
import pandas as pd , plotly . graph_objects as go
def main ():
covid , bitcoin , gold , dow = scrape_data ()
df = wrangle_data ( covid , bitcoin , gold , dow )
display_data ( df )
def scrape_data ():
def get_covid_cases ():
url = 'https://covid.ourworldindata.org/data/owid-covid-data.csv'
df = pd . read_csv ( url , usecols = [ 'location' , 'date' , 'total_cases' ])
df = df [ df . location == 'World' ]
return df . set_index ( 'date' ). total_cases
def get_ticker ( symbol ):
url = ( f'https://query1.finance.yahoo.com/v7/finance/download/ { symbol } ?'
'period1=1579651200&period2=9999999999&interval=1d&events=history' )
df = pd . read_csv ( url , usecols = [ 'Date' , 'Close' ])
return df . set_index ( 'Date' ). Close
out = get_covid_cases (), get_ticker ( 'BTC-USD' ), get_ticker ( 'GC=F' ), get_ticker ( '^DJI' )
names = [ 'Total Cases' , 'Bitcoin' , 'Gold' , 'Dow Jones' ]
return map ( pd . Series . rename , out , names )
def wrangle_data ( covid , bitcoin , gold , dow ):
df = pd . concat ([ bitcoin , gold , dow ], axis = 1 ) # Creates table by joining columns on dates.
df = df . sort_index (). interpolate () # Sorts rows by date and interpolates NaN-s.
df = df . loc [ '2020-02-23' :] # Discards rows before '2020-02-23'.
df = ( df / df . iloc [ 0 ]) * 100 # Calculates percentages relative to day 1.
df = df . join ( covid ) # Adds column with covid cases.
return df . sort_values ( df . index [ - 1 ], axis = 1 ) # Sorts columns by last day's value.
def display_data ( df ):
figure = go . Figure ()
for col_name in reversed ( df . columns ):
yaxis = 'y1' if col_name == 'Total Cases' else 'y2'
trace = go . Scatter ( x = df . index , y = df [ col_name ], name = col_name , yaxis = yaxis )
figure . add_trace ( trace )
figure . update_layout (
yaxis1 = dict ( title = 'Total Cases' , rangemode = 'tozero' ),
yaxis2 = dict ( title = '%' , rangemode = 'tozero' , overlaying = 'y' , side = 'right' ),
legend = dict ( x = 1.08 ),
width = 944 ,
height = 423
)
figure . show ()
if __name__ == '__main__' :
main ()Perpustakaan yang menyusun kode seperti Python menjadi C.
# $ pip3 install cython
import pyximport ; pyximport . install () # Module that runs imported Cython scripts.
import < cython_script > # Script needs a '.pyx' extension.
< cython_script > . main () # Main() isn't automatically executed. 'cdef' adalah opsional, tetapi mereka berkontribusi untuk mempercepat.'*' dan '&' , struct, serikat pekerja, dan enum. cdef < ctype / type > < var_name > [ = < obj > ]
cdef < ctype > [ n_elements ] < var_name > [ = < coll_of_nums > ]
cdef < ctype / type / void > < func_name > ( < ctype / type > < arg_name > ): ... cdef class < class_name > :
cdef public < ctype / type > < attr_name >
def __init__ ( self , < ctype / type > < arg_name > ):
self . < attr_name > = < arg_name >Sistem untuk menginstal perpustakaan langsung ke direktori Project.
$ python3 -m venv NAME # Creates virtual environment in current directory.
$ source NAME/bin/activate # Activates env. On Windows run `NAMEScriptsactivate`.
$ pip3 install LIBRARY # Installs the library into active environment.
$ python3 FILE # Runs the script in active environment. Also `./FILE`.
$ deactivate # Deactivates the active virtual environment. Jalankan skrip dengan '$ python3 FILE' atau '$ chmod u+x FILE; ./FILE' . Untuk secara otomatis memulai debugger ketika pengecualian tanpa baju terjadi menjalankan '$ python3 -m pdb -cc FILE' .
#!/usr/bin/env python3
#
# Usage: .py
#
from sys import argv , exit
from collections import defaultdict , namedtuple
from dataclasses import make_dataclass
from enum import Enum
import functools as ft , itertools as it , operator as op , re
def main ():
pass
###
## UTIL
#
def read_file ( filename ):
with open ( filename , encoding = 'utf-8' ) as file :
return file . readlines ()
if __name__ == '__main__' :
main ()'#<title>' di halaman web akan membatasi pencarian ke judul.'?' untuk mendapatkan tautan ke bagiannya.
