vsprintf

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

vsprintf — Return 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

User Contributed Notes 10 notes

down

spectrumcat ¶

8 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);

down

crash ¶

3 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.

down

Josef Kufner ¶

12 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);

}

?>

down

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.
*/

down

www dot wesley at gmail dot com ¶

16 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"
?>

down

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>';
    }
}
?>

down

Roadster ¶

18 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.

down

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;

?>

down

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.

down

ASchmidt at Anamera dot net ¶

7 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 );

add a note

vsprintf

Description

Parameters

Argnum

Width

Precision

Return Values

Errors/Exceptions

Changelog

Examples

See Also

User Contributed Notes 10 notes