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[![Image 1: PHP String Reference Manual]( PHP String Reference Manual]( ## Example Write some text into a file named "test.txt": The code above 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 a specified output stream (e.g., a file or database). Unlike fprintf(), in vfprintf() the arguments are passed as an array. Array elements are inserted at the percent (%) signs in the main string. The function processes them sequentially: the first array element is inserted at the first % sign, the second array element at the second % sign, and so on. **Note:** If there are more % signs than arguments in the array, you must use placeholders. Placeholders are inserted after the % sign and consist of a number followed by "$". See Example 2. **Tip:** Related functions: [fprintf()]( [printf()]( [sprintf()]( [vprintf()]( and [vsprintf()]( * * * ## Syntax vfprintf(_stream,format,argarray_) | Parameter | Description | | --- | --- | | _stream_ | Required. Specifies where to write/output the string. | | _format_ | Required. Specifies the string and how to format variables within it.
Possible format values:
* %% - Returns a percent sign %
* %b - Binary number
* %c - Character corresponding to an ASCII value
* %d - Signed decimal number (negative, zero, or positive)
* %e - Scientific notation using lowercase (e.g., 1.2e+2)
* %E - Scientific notation using uppercase (e.g., 1.2E+2)
* %u - Unsigned decimal number (greater than or equal to 0)
* %f - Floating-point number (locale-aware)
* %F - Floating-point number (not locale-aware)
* %g - Shorter of %e and %f
* %G - Shorter of %E and %f
* %o - Octal number
* %s - String
* %x - Hexadecimal number (lowercase)
* %X - Hexadecimal number (uppercase)

Additional format specifiers. These must be placed between % and the letter (e.g., %.2f):
* + (Prefixes numbers with + or - to indicate sign. By default, only negative numbers are marked; positive numbers are not)
* ' (Specifies the padding character, defaulting to space. Must be used together with a width specifier. Example: %'x20s uses "x" as padding)
* - (Left-aligns the value)
* (Specifies the minimum width of the value)
* . (Specifies the number of decimal places or maximum string length)

**Note:** If multiple format specifiers are used, they must appear in the order listed above. | | _argarray_ | Required. An array containing arguments to be inserted at the % signs in the format string. | ## Technical Details | Return Value: | Returns the length of the string that was written. | | --- | | PHP Version: | 5+ | * * * ## More Examples ## Example 1 Write some text into a file: The following text will be written to the file "test.txt": 123.000000456.000000 ## Example 2 Using placeholders: The following text will be written to the file "test.txt": With 2 decimals: 123.00 With no decimals: 123 ## Example 3 Using printf() to demonstrate all possible format values: ",$num1); // Binary number printf("%%c = %c
",$char); // The ASCII Character printf("%%d = %d
",$num1); // Signed decimal number printf("%%d = %d
",$num2); // Signed decimal number printf("%%e = %e
",$num1); // Scientific notation (lowercase) printf("%%E = %E
",$num1); // Scientific notation (uppercase) printf("%%u = %u
",$num1); // Unsigned decimal number (positive) printf("%%u = %u
",$num2); // Unsigned decimal number (negative) printf("%%f = %f
",$num1); // Floating-point number (local settings aware) printf("%%F = %F
",$num1); // Floating-point number (not local settings aware) printf("%%g = %g
",$num1); // Shorter of %e and %f printf("%%G = %G
",$num1); // Shorter of %E and %f printf("%%o = %o
",$num1); // Octal number printf("%%s = %s
",$num1); // String printf("%%x = %x
",$num1); // Hexadecimal number (lowercase) printf("%%X = %X
",$num1); // Hexadecimal number (uppercase) printf("%%+d = %+d
",$num1); // Sign specifier (positive) printf("%%+d = %+d
",$num2); // Sign specifier (negative) ?> [Run Example »]( * * * [![Image 2: PHP String Reference Manual]( PHP String Reference Manual](