PHP vfprintf() function

PHP String Function

Example

Write the text to the text file named "test.txt":

<?php
$number = 9;
$str = "Beijing";
$file = fopen("test.txt", "w");
echo vfprintf($file,"There are 쥕lion 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 the formatted string to the specified output stream (e.g., a file or database).

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

Comment:If the % symbol is more than arg If there are parameters, you must use placeholders. Placeholders are inserted after the % symbol and consist of a number and "\$". See example 2.

Related functions:

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 the variables within it.

Possible format values:

  • %% - Returns a percentage sign %
  • %b - Binary number
  • %c - Character corresponding to ASCII value
  • %d - Decimal number with a sign (negative, 0, positive)
  • %e - Uses lowercase scientific notation (e.g., 1.2e+2)
  • %E - Uses uppercase scientific notation (e.g., 1.2E+2)
  • 蒝ecimal number without a sign (greater than or equal to 0)
  • %f - Floating-point number (localized)
  • %F - Floating-point number (non-localized)
  • %g - Shorter than %e and %f
  • %G - Shorter than %E and %f
  • %o - Octal number
  • %s - String
  • %x - Hexadecimal number (lowercase letters)
  • %X - Hexadecimal number (uppercase letters)

Additional format values. They must be placed between % and a letter (e.g., %.2f):

  • + (Add + or - in front of a number to define its sign. By default, only negative numbers are marked, and positive numbers are not.)
  • ' (specifies what to use as padding, the default is space. It must be used with the width specifier. For example: '%x20s' (using 'x' as padding))
  • - (left-adjust the variable value)
  • .[0-9] (specifies the minimum width of the variable value)
  • .[0-9] (specifies the number of decimal places or maximum string length)

Comment:If multiple format specifiers are used, they must be in the order specified above.
argarray Required. An array with parameters that will be inserted format At the % symbol in the string.

Technical details

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

More examples

Example 1

Write text to the 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

Using placeholders:

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

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

With 2 decimals: 123.00
With no decimals: 123

Example 3

Use printf() to demonstrate all possible format values:

<?php
$num1 = 123456789;
$num2 = -123456789;
$char = 50; // ASCII character 50 is 2
// Comment: The format value "%%" returns a percent sign
printf("%%b = %%b <br>", $num1); // Binary number
printf("%%c = %%c <br>", $char); // ASCII character
printf("%%d = %%d <br>", $num1); // Signed decimal number
printf("%%d = %%d <br>", $num2); // Signed decimal number
printf("%%e = %%e <br>", $num1); // Scientific notation (lowercase)
printf("%%E = %%E <br>", $num1); // Scientific notation (uppercase)
printf("%鑾u <br>", $num1); // Unsigned Decimal Number (Positive)
printf("%鑾u <br>", $num2); // Unsigned Decimal Number (Negative)
printf("%%f = %f <br>", $num1); // Floating Point Number (Respecting local settings)
printf("%%F = %F <br>", $num1); // Floating Point Number (Not respecting local settings)
printf("%%g = %g <br>", $num1); // Shorter than %e and %f
printf("%%G = %G <br>", $num1); // Shorter than %E and %f
printf("%%o = %o <br>", $num1); // Octal Number
printf("%%s = %s <br>", $num1); // String
printf("%%x = %x <br>", $num1); // Hexadecimal Number (Lowercase)
printf("%%X = %X <br>", $num1); // Hexadecimal Number (Uppercase)
printf("%%+d = %+d <br>", $num1); // Positive Sign Indicator
printf("%%+d = %+d <br>", $num2); // Negative Sign Indicator
?>

Run Instance

PHP String Function