Output formatted string:
<?php$number = 9;$str = "Beijing";printf("There are %u million bicycles in %s.",$number,$str);?>The printf() function outputs a formatted string.
The arg1, arg2, ++ parameters will be inserted into the main string at the percent sign (%) symbol. This function is executed step by step. At the first % sign, insert arg1, at the second % sign, insert arg2, 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 "$". See Example 2.
Tip: Related functions: sprintf(), vprintf(), vsprintf(), fprintf(), and vfprintf()
printf( format,arg1,arg2,arg++ )
| parameter | describe |
|---|---|
| format | Required. Specifies a string and how to format variables within it. Possible format values: %% - returns a percent sign % %b - binary number %c - the character corresponding to the ASCII value %d - Decimal number with sign (negative, 0, positive) %e - Use lowercase scientific notation (e.g. 1.2e+2) %E - Use uppercase scientific notation (e.g. 1.2E+2) %u - Decimal number without sign (greater than or equal to 0) %f - floating point number (local setting) %F - floating point number (non-native setting) %g - the shorter version of %e and %f %G - shorter %E and %f %o - octal number %s - string %x - Hexadecimal number (lowercase letters) %X - hexadecimal number (uppercase letters) Additional format values. Must be placed between % and a letter (e.g. %.2f): + (Add + or - in front of a number to define the sign of the number. By default, only negative numbers are marked, and positive numbers are not marked) ' (Specifies what to use as padding, defaults to spaces. It must be used with a width specifier. For example: %'x20s (use "x" as padding)) - (left adjustment variable value) [0-9] (specifies the minimum width of the variable value) .[0-9] (specifies the number of decimal places or the maximum string length) Note: If multiple above format values are used, they must be used in the order above and cannot be disrupted. |
| arg1 | Required. Specifies the parameters to be inserted at the first % sign in the format string. |
| arg2 | Optional. Specifies the parameters to be inserted into the format string at the second % sign. |
| arg++ | Optional. Specifies the parameters to be inserted into the format string at the third, fourth, etc. % symbols. |
| Return value: | Returns the length of the output string. |
|---|---|
| PHP version: | 4+ |
Use the format value %f:
<?php$number = 123;printf("%f",$number);?>Use placeholders:
<?php$number = 123;printf("With 2 decimals: %1$.2f<br>With no decimals: %1$u",$number);?>Demonstration of all possible format values:
<?php$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)?>Demonstration of string specifiers:
<?php$str1 = "Hello";$str2 = "Hello world!";printf("[%s]<br>",$str1);printf("[%8s]<br>",$str1) ;printf("[%-8s]<br>",$str1);printf("[%08s]<br>",$str1); printf("[%'*8s]<br>",$str1);printf("[%8.8s]<br>",$str2);?>