vsprintf

(PHP 4 >= 4.1.0, PHP 5, PHP 7, PHP 8)

vsprintfReturn a formatted string

Description

vsprintf(string $format, array $values): string

Operates as sprintf() but accepts an array of arguments, rather than a variable number of arguments.

Parameters

format

The format string is composed of zero or more directives: ordinary characters (excluding %) that are copied directly to the result and conversion specifications, each of which results in fetching its own parameter.

A conversion specification follows this prototype: %[argnum$][flags][width][.precision]specifier.

Argnum

An integer followed by a dollar sign $, to specify which number argument to treat in the conversion.

Flags
Flag Description
- Left-justify within the given field width; Right justification is the default
+ Prefix positive numbers with a plus sign +; Default only negative are prefixed with a negative sign.
(space) Pads the result with spaces. This is the default.
0 Only left-pads numbers with zeros. With s specifiers this can also right-pad with zeros.
'(char) Pads the result with the character (char).

Width

Either an integer that says how many characters (minimum) this conversion should result in, or *. If * is used, then the width is supplied as an additional integer value preceding the one formatted by the specifier.

Precision

A period . optionally followed by either an integer or *, whose meaning depends on the specifier:

  • For e, E, f and F specifiers: this is the number of digits to be printed after the decimal point (by default, this is 6).
  • For g, G, h and H specifiers: this is the maximum number of significant digits to be printed.
  • For s specifier: it acts as a cutoff point, setting a maximum character limit to the string.

Note: If the period is specified without an explicit value for precision, 0 is assumed. If * is used, the precision is supplied as an additional integer value preceding the one formatted by the specifier.

Specifiers
Specifier Description
% A literal percent character. No argument is required.
b The argument is treated as an integer and presented as a binary number.
c The argument is treated as an integer and presented as the character with that ASCII.
d The argument is treated as an integer and presented as a (signed) decimal number.
e The argument is treated as scientific notation (e.g. 1.2e+2).
E Like the e specifier but uses uppercase letter (e.g. 1.2E+2).
f The argument is treated as a float and presented as a floating-point number (locale aware).
F The argument is treated as a float and presented as a floating-point number (non-locale aware).
g

General format.

Let P equal the precision if nonzero, 6 if the precision is omitted, or 1 if the precision is zero. Then, if a conversion with style E would have an exponent of X:

If P > X ≥ −4, the conversion is with style f and precision P − (X + 1). Otherwise, the conversion is with style e and precision P − 1.

G Like the g specifier but uses E and f.
h Like the g specifier but uses F. Available as of PHP 8.0.0.
H Like the g specifier but uses E and F. Available as of PHP 8.0.0.
o The argument is treated as an integer and presented as an octal number.
s The argument is treated and presented as a string.
u The argument is treated as an integer and presented as an unsigned decimal number.
x The argument is treated as an integer and presented as a hexadecimal number (with lowercase letters).
X The argument is treated as an integer and presented as a hexadecimal number (with uppercase letters).

Warning

The c type specifier ignores padding and width

Warning

Attempting to use a combination of the string and width specifiers with character sets that require more than one byte per character may result in unexpected results

Variables will be co-erced to a suitable type for the specifier:

Type Handling
Type Specifiers
string s
int d, u, c, o, x, X, b
float e, E, f, F, g, G, h, H

values

Return Values

Return array values as a formatted string according to format.

Errors/Exceptions

As of PHP 8.0.0, a ValueError is thrown if the number of arguments is zero. Prior to PHP 8.0.0, a E_WARNING was emitted instead.

As of PHP 8.0.0, a ValueError is thrown if [width] is less than zero or bigger than PHP_INT_MAX. Prior to PHP 8.0.0, a E_WARNING was emitted instead.

As of PHP 8.0.0, a ValueError is thrown if [precision] is less than zero or bigger than PHP_INT_MAX. Prior to PHP 8.0.0, a E_WARNING was emitted instead.

As of PHP 8.0.0, a ValueError is thrown when less arguments are given than required. Prior to PHP 8.0.0, false was returned and a E_WARNING emitted instead.

Changelog

Version Description
8.0.0 This function no longer returns false on failure.
8.0.0 Throw a ValueError if the number of arguments is zero; previously this function emitted a E_WARNING instead.
8.0.0 Throw a ValueError if [width] is less than zero or bigger than PHP_INT_MAX; previously this function emitted a E_WARNING instead.
8.0.0 Throw a ValueError if [precision] is less than zero or bigger than PHP_INT_MAX; previously this function emitted a E_WARNING instead.
8.0.0 Throw a ValueError when less arguments are given than required; previously this function emitted a E_WARNING instead.

Examples

Example #1 vsprintf(): zero-padded integers

<?php
print vsprintf("%04d-%02d-%02d", explode('-', '1988-8-1'));
?>

The above example will output:

1988-08-01

See Also

  • printf() - Output a formatted string
  • sprintf() - Return a formatted string
  • fprintf() - Write a formatted string to a stream
  • vprintf() - Output a formatted string
  • vfprintf() - Write a formatted string to a stream
  • sscanf() - Parses input from a string according to a format
  • fscanf() - Parses input from a file according to a format
  • number_format() - Format a number with grouped thousands
  • date() - Format a Unix timestamp

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User Contributed Notes 10 notes

up
43
spectrumcat
7 years ago
Instead of inventing own functions in case you'd like to use array keys as placeholder names and replace corresponding array values in a string, just use the str_replace:

$string = 'Hello %name!';
$data = array(
  '%name' => 'John'
);

$greeting = str_replace(array_keys($data), array_values($data), $string);
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5
crash
2 years ago
Note that this function now throws an ValueError* as of PHP 8.0 if there is an error:

$ php -r 'var_dump(vsprintf("%d", []));'
> Fatal error: Uncaught ValueError: The arguments array must contain 1 items, 0 given in Command line code:1

*ValueError is new in PHP 8.0, so if you want to make your code compatible to PHP 7.x you should test that the arguments array has the correct length.
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14
Josef Kufner
11 years ago
<?php
/**
* Like vsprintf, but accepts $args keys instead of order index.
* Both numeric and strings matching /[a-zA-Z0-9_-]+/ are allowed.
*
* Example: vskprintf('y = %y$d, x = %x$1.1f', array('x' => 1, 'y' => 2))
* Result:  'y = 2, x = 1.0'
*
* $args also can be object, then it's properties are retrieved
* using get_object_vars().
*
* '%s' without argument name works fine too. Everything vsprintf() can do
* is supported.
*
* @author Josef Kufner <jkufner(at)gmail.com>
*/
function vksprintf($str, $args)
{
    if (
is_object($args)) {
       
$args = get_object_vars($args);
    }
   
$map = array_flip(array_keys($args));
   
$new_str = preg_replace_callback('/(^|[^%])%([a-zA-Z0-9_-]+)\$/',
            function(
$m) use ($map) { return $m[1].'%'.($map[$m[2]] + 1).'$'; },
           
$str);
    return
vsprintf($new_str, $args);
}
?>
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1
steven at nevvix dot com
6 years ago
<?php
/**
* Return a formatted string like vsprintf() with named placeholders.
*
* When a placeholder doesn't have a matching key in `$args`,
*   the placeholder is returned as is to see missing args.
* @param string $format
* @param array $args
* @param string $pattern
* @return string
*/
function p($format, array $args, $pattern="/\{(\w+)\}/") {
    return
preg_replace_callback($pattern, function ($matches) use ($args) {
        return @
$args[$matches[1]] ?: $matches[0];
    },
$format);
}

$args = ["database"=>"people", "user"=>"staff", "pass"=>"pass123", "host"=>"localhost"];

// With PHP-like placeholders: the variable is embedded in a string "{$database}" but without the dollar sign
$format = <<<SQL
CREATE DATABASE IF NOT EXISTS {database};
GRANT ALL PRIVILEGES ON {database_name}.* TO '{user}'@'{host}';
SET PASSWORD = PASSWORD('{pass}');
SQL;
echo
p($format, $args);
/*
Result:

CREATE DATABASE IF NOT EXISTS people;
GRANT ALL PRIVILEGES ON {database_name}.* TO 'staff'@'localhost';
SET PASSWORD = PASSWORD('pass123');

The `{database_name}` placeholder doesn't exist as a matching key in `$args` so it's returned as is.
*/

// With Ruby-like placeholders
$format = <<<SQL
CREATE DATABASE IF NOT EXISTS :database;
GRANT ALL PRIVILEGES ON :database_name.* TO ':user'@':host';
SET PASSWORD = PASSWORD(':pass');
SQL;
echo
p($format, $args, "/:(\w+)/");
/*
Result:

CREATE DATABASE IF NOT EXISTS people;
GRANT ALL PRIVILEGES ON :database_name.* TO 'staff'@'localhost';
SET PASSWORD = PASSWORD('pass123');

The `:database_name` placeholder doesn't exist as a matching key in `$args` so it's returned as is.
*/
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4
www dot wesley at gmail dot com
15 years ago
vnsprintf is equal to vsprintf except for associative, signed or floating keys.

vnsprintf supports for example "%assocKey$05d", "%-2$'+10s" and "%3.2$05u", vsprintf doesn't

vnsprintf( '%2$d', $array) [2nd value] is equal to vsprintf( '%2$d', $array) [2nd value]
vnsprintf( '%+2$d', $array) [key = 2] is equal to vnsprintf( '%2.0$d', $array) [key = 2]
vnsprintf( '%+2$d', $array) [key = 2] is different of vsprintf( '%+2$d', $array) [unsupported]

When you use signed or floating keys, vnsprintf searchs for the signed truncated key of the original array

Note¹: vnsprintf does not support for example "%someKeyf" (floating number, key = someKey) or "%+03d" (signed decimal number, key = 3), you should use "%someKey$f" or "%+03$d" respectively.
Note²: "%+03d" (or "%1$+03d") will be interpreted as signed zero-padded decimal number

<?php
function vnsprintf( $format, array $data)
{
   
preg_match_all( '/ (?<!%) % ( (?: [[:alpha:]_-][[:alnum:]_-]* | ([-+])? [0-9]+ (?(2) (?:\.[0-9]+)? | \.[0-9]+ ) ) ) \$ [-+]? \'? .? -? [0-9]* (\.[0-9]+)? \w/x', $format, $match, PREG_SET_ORDER | PREG_OFFSET_CAPTURE);
   
$offset = 0;
   
$keys = array_keys($data);
    foreach (
$match as &$value )
    {
        if ( (
$key = array_search( $value[1][0], $keys) ) !== FALSE || ( is_numeric( $value[1][0]) && ( $key = array_search( (int)$value[1][0], $keys) ) !== FALSE ) ) {
           
$len = strlen( $value[1][0]);
           
$format = substr_replace( $format, 1 + $key, $offset + $value[1][1], $len);
           
$offset -= $len - strlen( $key);
        }
    }
    return
vsprintf( $format, $data);
}

$examples = array(
   
2.8=>'positiveFloat',    // key = 2 , 1st value
   
-3=>'negativeInteger',    // key = -3 , 2nd value
   
'my_name'=>'someString'    // key = my_name , 3rd value
);

echo
vsprintf( "%%my_name\$s = '%my_name\$s'\n", $examples);    // [unsupported]
echo vnsprintf( "%%my_name\$s = '%my_name\$s'\n", $examples);    // output : "someString"

echo vsprintf( "%%2.5\$s = '%2.5\$s'\n", $examples);        // [unsupported]
echo vnsprintf( "%%2.5\$s = '%2.5\$s'\n", $examples);        // output : "positiveFloat"

echo vsprintf( "%%+2.5\$s = '%+2.5\$s'\n", $examples);        // [unsupported]
echo vnsprintf( "%%+2.5\$s = '%+2.5\$s'\n", $examples);        // output : "positiveFloat"

echo vsprintf( "%%-3.2\$s = '%-3.2\$s'\n", $examples);        // [unsupported]
echo vnsprintf( "%%-3.2\$s = '%-3.2\$s'\n", $examples);        // output : "negativeInteger"

echo vsprintf( "%%2\$s = '%2\$s'\n", $examples);            // output : "negativeInteger"
echo vnsprintf( "%%2\$s = '%2\$s'\n", $examples);            // output : [= vsprintf]

echo vsprintf( "%%+2\$s = '%+2\$s'\n", $examples);        // [unsupported]
echo vnsprintf( "%%+2\$s = '%+2\$s'\n", $examples);        // output : "positiveFloat"

echo vsprintf( "%%-3\$s = '%-3\$s'\n", $examples);        // [unsupported]
echo vnsprintf( "%%-3\$s = '%-3\$s'\n", $examples);        // output : "negativeInteger"
?>
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4
jon at ardentcreative dot co dot uk
18 years ago
This can be used for quick and dirty internationalization:

<?php
$GLOBALS
['strings']['example'] = "There are %d people.";

// Loads a phrase from the translations list in lang/$lang/phrases.php
function t() {
   
$args = func_get_args();
   
$nArgs = func_num_args();
   
   
$phrase = array_shift($args);
   
$nArgs--;
   
    include_once(
"../lang/" . lang() . "/phrases.php");
    if (isset(
$GLOBALS['strings'][$phrase])) {
        return
vsprintf($GLOBALS['strings'][$phrase], $args);
    } else {
        return
'<span style="color: #ff0000">Untranslated string: ' . $phrase . '</span>';
    }
}
?>
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4
Roadster
17 years ago
Please note: The same functionality (sortof) can be attained between version 4.0.4 and 4.1.0 using call_user_func_array.

Example:

call_user_func_array("sprintf", $arg)

First element of $arg is the format. This rescued me in a situation where version 4.1.0 wasn't available.
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2
dee jay simple zero07 at geemail dawt co
11 years ago
Using a heredoc with vprintf:

<?php
$string
= <<<THESTRING
I like the state of %1\$s <br />
I picked: %2\$d as a number, <br />
I also picked %2\$d as a number again <br />
%3\$s<br />
THESTRING;

$returnText = vprintf$string, array('Oregon','7','I Love Oregon')  );

echo
$returnText;
?>
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1
jed at NOSPAM dot jed dot bz
20 years ago
vsprintf() accepts arrays with any keys, so the array_shift() technique is unnecessary when writing a printf-type function. Any parameters you require are easily unset from the array you retrieve with func_get_args():

<?php

function mysprintf($format) {
   
$args = func_get_args();
    unset(
$args[0]); /* get rid of "$format" */
   
return vsprintf($format, $args);
}

/* I use this technique in production code as follows: */
function logf($target, $string) {
   
$args = func_get_args();
    unset(
$args[0], $args[1]);
   
fprintf($GLOBALS['config']['logtargets'][$target],
       
"[%s] %s\n", date('H:i'), wordwrap(vsprintf($string, $args), 75, '\n\r '));
}

/* e.g.:
    logf(DEBUG, "Oops! %s", mysql_error());
*/

?>

array_shift() and other costly array operations aren't required, as far as I know. I could be wrong.
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1
ASchmidt at Anamera dot net
6 years ago
It's necessary to clearly how to apply argument swapping when using an array of arguments. One might be tempted to use %0$ to reference $args[0].

In reality, the position specifier is always the array index+1:

$args[0]  is referenced by %1$...
$args[1]  is referenced by %2$...
etc.

Similarly, the first subpattern of a RegEx match would be found in $matches[1], the second in $match[2], etc. However if the $matches array is used as arguments to vsprint(), then the position specifier is subpattern+1:

preg_match( $pattern, $subject, $matches );
vsprintf( 'Full Match = %1$s, first Subpattern = %2$s, second Subpattern = %3$s', $matches );
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