PHP vfprintf() function

Example

Write some text to a text file named "test.txt":

<?php$number = 9;$str = "Beijing";$file = fopen("test.txt","w");echo vfprintf($file,"There are %u million bicycles in %s.", array($number,$str));?>

The above code will output:

40

The following text will be written to the file "test.txt":

There are 9 million bicycles in Beijing.

Definition and usage

The vfprintf() function writes a formatted string to the specified output stream (for example: file or database).

Unlike fprintf(), the parameters in vfprintf() are in an array. Array elements will be inserted into the main string at the percent sign (%). This function is executed step by step. At the first % sign, the first array element is inserted, at the second % sign, the second array element is inserted, and so on.

Note: If there are more % symbols than arg parameters, you must use placeholders. The placeholder is inserted after the % symbol and consists of a number and "$". See Example 2.

Tip: Related functions: fprintf(), printf(), sprintf(), vprintf() and vsprintf()

grammar

 vfprintf( stream,format,argarray )

parameter	describe
stream	Required. Specifies where strings are written/output.
format	Required. Specifies a string and how variables within it should be formatted. Possible format values: %% - returns a percent sign % %b - binary number %c - the character corresponding to the ASCII value %d - decimal number with sign (negative, 0, positive) %e - Use lowercase scientific notation (e.g. 1.2e+2) %E - Use uppercase scientific notation (e.g. 1.2E+2) %u - Decimal number without sign (greater than or equal to 0) %f - floating point number (local setting) %F - floating point number (non-native setting) %g - the shorter version of %e and %f %G - shorter %E and %f %o - octal number %s - string %x - hexadecimal number (lowercase letters) %X - hexadecimal number (uppercase letters) Additional format values. Must be placed between % and a letter (e.g. %.2f): + (Add + or - in front of a number to define the sign of the number. By default, only negative numbers are marked, and positive numbers are not marked) ' (Specifies what to use as padding, defaults to spaces. It must be used with a width specifier. For example: %'x20s (use "x" as padding)) - (left adjustment variable value) [0-9] (specifies the minimum width of the variable value) .[0-9] (specifies the number of decimal places or the maximum string length) Note: If multiple above format values ​​are used, they must be used in the order above and cannot be disrupted.
argarray	Required. An array with parameters that will be inserted into the format string at % symbols.

technical details

Return value:	Returns the length of the string being written.
PHP version:	5+

More examples

Example 1

Write some text to a file:

<?php$num1 = 123;$num2 = 456;$file = fopen("test.txt","w");vfprintf($file,"%f%f",array($num1,$num2)) ;?>

The following text will be written to the file "test.txt":

123.000000456.000000

Example 2

Use placeholders:

<?php$number = 123;$file = fopen("test.txt","w");vfprintf($file,"With 2 decimals: %1$.2fnWith no decimals: %1$u",array( $number));?>

The following text will be written to the file "test.txt":

With 2 decimals: 123.00With no decimals: 123

Example 3

Use printf() to demonstrate all possible format values:

<?php$num1 = 123456789;$num2 = -123456789;$char = 50; // The ASCII Character 50 is 2// Note: The format value "%%" returns a percent signprintf("%%b = %b <br>",$num1); // Binary numberprintf("%%c = %c <br>",$char); // The ASCII Characterprintf("%%d = %d <br>",$num1); // Signed decimal numberprintf("%%d = %d <br>",$num2); // Signed decimal numberprintf("%%e = %e <br>",$num1); // Scientific notation (lowercase)printf("%%E = %E <br>",$num1); // Scientific notation (uppercase)printf("%%u = %u <br>",$num1); // Unsigned decimal number (positive)printf("%%u = %u <br>",$num2); // Unsigned decimal number (negative)printf("%%f = %f <br>",$num1); // Floating-point number (local settings aware)printf("%%F = %F <br>",$num1); // Floating-point number (not local settings aware)printf("%%g = %g <br>",$num1); // Shorter of %e and %fprintf(" %%G = %G <br>",$num1); // Shorter of %E and %fprintf("%%o = %o <br>",$num1); // Octal numberprintf("%%s = %s <br>",$num1); // Stringprintf("%%x = %x <br>",$num1); // Hexadecimal number (lowercase)printf("%%X = %X <br >",$num1); // Hexadecimal number (uppercase)printf("%%+d = %+d <br>",$num1); // Sign specifier (positive)printf("%%+d = %+d <br>",$num2); // Sign specifier (negative)?>