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PHP vprintf() Function

< PHP String Reference

Example

Output a formatted string:

<?php
$number = 9;
$str = "Beijing";
vprintf("There are %u million bicycles in %s.",array($number,$str));
?>
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Definition and Usage

The vprintf() function outputs a formatted string.

Unlike printf() , the arguments in vprintf() , are placed in an array. The array elements will be inserted at the percent (%) signs in the main string. This function works "step-by-step". At the first % sign, the first array element is inserted, at the second % sign, the second array element is inserted, etc.

Note: If there are more % signs than arguments, you must use placeholders. A placeholder is inserted after the % sign, and consists of the argument- number and "\$". See example two.

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

Syntax

vprintf(format,argarray)

Parameter Description
format Required. Specifies the string and how to format the variables in it.

Possible format values:

  • %% - Returns a percent sign
  • %b - Binary number
  • %c - The character according to the ASCII value
  • %d - Signed decimal number (negative, zero or positive)
  • %e - Scientific notation using a lowercase (e.g. 1.2e+2)
  • %E - Scientific notation using a uppercase (e.g. 1.2E+2)
  • %u - Unsigned decimal number (equal to or greather than zero)
  • %f - Floating-point number (local settings aware)
  • %F - Floating-point number (not local settings aware)
  • %g - shorter of %e and %f
  • %G - shorter of %E and %f
  • %o - Octal number
  • %s - String
  • %x - Hexadecimal number (lowercase letters)
  • %X - Hexadecimal number (uppercase letters)

Additional format values. These are placed between the % and the letter (example %.2f):

  • + (Forces both + and - in front of numbers. By default, only negative numbers are marked)
  • ' (Specifies what to use as padding. Default is space. Must be used together with the width specifier. Example: %'x20s (this uses "x" as padding)
  • - (Left-justifies the variable value)
  • [0-9] (Specifies the minimum width held of to the variable value)
  • .[0-9] (Specifies the number of decimal digits or maximum string length)

Note: If multiple additional format values are used, they must be in the same order as above.
argarray Required. An array with arguments to be inserted at the % signs in the format string

Technical Details

Return Value: Returns the length of the outputted string
PHP Version: 4.1.0+

More Examples

Example 1

Using the format value %f:

<?php
$num1 = 123;
$num2 = 456;
vprintf("%f%f",array($num1,$num2));
?>
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Example 2

Use of placeholders:

<?php
$number = 123;
vprintf("With 2 decimals: %1\$.2f
<br>With no decimals: %1\$u",array($number));
?>
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Example 3

Using 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 sign
printf("%%b = %b <br>",$num1); // Binary number
printf("%%c = %c <br>",$char); // The 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("%%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>",$num1); // Shorter of %e and %f
printf("%%G = %G <br>",$num1); // Shorter of %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>",$num1); // Sign specifier (positive)
printf("%%+d = %+d <br>",$num2); // Sign specifier (negative)
?>
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Example 4

A demonstration of string specifiers:

<?php
$str1 = "Hello";
$str2 = "Hello world!";

vprintf("[%s]<br>",array($str1));
vprintf("[%8s]<br>",array($str1));
vprintf("[%-8s]<br>",array($str1));
vprintf("[%08s]<br>",array($str1));
vprintf("[%'*8s]<br>",array($str1));
vprintf("[%8.8s]<br>",array($str2));
?>
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< PHP String Reference