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    vprintf

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

    vprintf — Output a formatted string

    Description

    function vprintf(string $format, array $values): int

    Display array values as a formatted string according to format (which is described in the documentation for sprintf()).

    Operates as printf() 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

    Returns the length of the outputted string.

    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 vprintf(): zero-padded integers

    <?php
vprintf("%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
    • vsprintf() - Return 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 8 notes

    up
    11
    steve at stevelockwood dot net
    11 years ago
    If, instead of an array, you pass an object PHP will automatically cast the object as an array so you can use it directly in vprintf.
<?php
 $object = new stdClass();
 $object->Property1 = 'Value 1';
 $object->Property2 = 'Value 2';
vprintf('%-20s %-20s', $object);

/* will output
 Value 1              Value 2             
*/
?>
    up
    1
    phpcoder at gmail dot com
    6 years ago
    Using the ... operator, vprintf($format, $array) is basically just printf($format, ...$array).
    up
    0
    tehjosh at gamingg dot net
    18 years ago
    To toolofthesystem at gmail dot com:

You don't need to use output buffering with vprintf() because you can use vsprintf(), which has the same functionality as vprintf(), except that it returns the resulting string instead of outputting it.
    up
    -1
    taken from &#34;Php Phrasebook&#34;
    18 years ago
    <?php
$string = 'The site runs on PHP '.phpversion();
preg_match('/php ((\d)\.\d\.\d+)/i',$string,$matches);
print_r($matches);
vprintf('Match: %s<br /> Version %s; Major:%d.',$matches);
?>

output:
Array ( [0] => PHP 5.2.5 [1] => 5.2.5 [2] => 5 ) 
Match: PHP 5.2.5 Version 5.2.5; Major:5.

For preg_match:

If matches  is provided, then it is filled with the results of search. $matches[0] will contain the text that matched the full pattern, $matches[1]  will have the text that matched the first captured parenthesized subpattern, and so on.
    up
    -2
    Chris
    13 years ago
    Another way to display arrays is use an array_walk(). This can be useful inline echo/print where a foreach wouldn't work, e.g.

<?php
echo "These errors: ", (unset)array_walk($msgs, function($a) { echo "<p>$a</p>"; } ), "must be corrected.";
?>
    up
    -2
    toolofthesystem at gmail dot com
    19 years ago
    This function comes useful sometimes when trying to list information returned from MySQL:

function print_sql($query,$printf){
    $sql_sql = mysql_query($query);
    while($sql = mysql_fetch_row($sql_sql)){
        vprintf($printf,$sql);
    }
}

Unfortunately, this seems to sneak its way past output buffering when I tried creating an argument to allow it to be contained in a returned string... either that or I didn't do it right.
    up
    -2
    caleb at tekhawk dot com
    19 years ago
    i know that you can use %1$s or %3$s to select the first or third string but how can you or can you use array names to select it

something like %'user'$s $'email'$s

i tend to add things to my databases over time and this could save loads of recoding
    up
    -5
    badcop666 at hotmail dot com
    18 years ago
    For blocks of text, sprintf() is slow according to my tests. 

Also, having the mapping between place-holders and the list of actual variables or datastructures often makes this code difficult to read. But the printf() family are widely supported and have a huge range of nice features. Performance is a cold mistress though!

From an ease-of-reading and maintenance, debugging point of view, I much prefer HEREDOC and "...{$variable}..." methods.

For a block of HTML markup with place holders, the fastest by far was:-

?>
<div> markup etc<?= $variable ?>more markup
<?

My tests comprised 20 runs of a loop of 1 million iterations with output buffering, ditching the buffer on each loop.

The timings ranged from average 2.1msec/million repetitions for the <?= $var ?> method up to 7.6msec/million using printf().

I'll try some benchmarking tools too, since I just wrote this myself and it could be introducing bias, but they've run on dev servers with low load.

Hopefully interesting.
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