array_product

    (PHP 5 >= 5.1.0, PHP 7, PHP 8)

    array_product — Calcule le produit des valeurs du tableau

    Description

    array_product(array $array): int|float

    array_product() retourne le produit des valeurs du tableau array.

    Liste de paramètres

    array

    Le tableau.

    Valeurs de retour

    Retourne le produit, sous la forme d'un entier ou d'un nombre décimal.

    Historique

    Version Description
    8.3.0 Émet désormais un E_WARNING lorsque les valeurs de type array ne peuvent pas être converties en entier ou nombre décimal. Auparavant, les tableaux et les objets étaient ignorés tandis que toutes les autres valeurs étaient converties en entier. De plus, les objets définissant une conversion numérique (par exemple, GMP) sont désormais convertis au lieu d'être ignorés.

    Exemples

    Exemple #1 Exemple avec array_product()

    <?php

    $a     = array(2, 4, 6, 8);
    echo     "produit(a) = " . array_product($a) . "\n";
    echo     "product(array()) = " . array_product(array()) . "\n";

    ?>

    L'exemple ci-dessus va afficher :

    produit(a) = 384
product(array()) = 1

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    User Contributed Notes 6 notes

    up
    29
    Andre D
    18 years ago
    This function can be used to test if all values in an array of booleans are TRUE.

    Consider:

    <?php

    function outbool($test)
    {
    return (bool)     $test;
    }

    $check[] = outbool(TRUE);
    $check[] = outbool(1);
    $check[] = outbool(FALSE);
    $check[] = outbool(0);

    $result = (bool) array_product($check);
    // $result is set to FALSE because only two of the four values evaluated to TRUE

    ?>

    The above is equivalent to:

    <?php

    $check1     = outbool(TRUE);
    $check2 = outbool(1);
    $check3 = outbool(FALSE);
    $check4 = outbool(0);

    $result = ($check1 && $check2 && $check3 && $check4);

    ?>

    This use of array_product is especially useful when testing an indefinite number of booleans and is easy to construct in a loop.
    up
    11
    bsr dot anwar at gmail dot com
    7 years ago
    Here's how you can find a factorial of a any given number with help of range and array_product functions.

    function factorial($num) {
    return array_product(range(1, $num));
    }

    printf("%d", factorial(5)); //120
    up
    0
    gergely dot lukacsy at streamnet dot hu
    1 year ago
    Just a little correction for Andre D's answer: "(bool) array_product($array);" is equivalent with the conjunction of each array elements of $array, UNLESS the provided array is empty in which case array_product() will return 1, which will translate to boolean TRUE.

    To mitigate this, you should expand the function with an additional check:

    <?php

    $result     = !empty($check) && !!array_product($check);

    ?>
    up
    0
    biziclop
    2 years ago
    You can use array_product() to calculate the geometric mean of an array of numbers:

    <?php
    $a     = [ 1, 10, 100 ];
    $geom_avg = pow( array_product( $a ), 1 / count( $a ));
    // = 9.999999999999998 ≈ 10
    ?>
    up
    0
    Marcel G
    14 years ago
    You can use array_product to calculate the factorial of n:
    <?php
    function factorial( $n )
    {
    if(     $n < 1 ) $n = 1;
    return     array_product( range( 1, $n ));
    }
    ?>

    If you need the factorial without having array_product available, here is one:
    <?php
    function factorial( $n )
    {
    if(     $n < 1 ) $n = 1;
    for(     $p++; $n; ) $p *= $n--;
    return     $p;
    }
    ?>
    up
    -5
    Jimmy PHP
    10 years ago
    array_product() can be used to implement a simple boolean AND search

    <?php
    $args     = array('first_name'=>'Bill','last_name'=>'Buzzard');
    $values[] = array('first_name'=>'Brenda','last_name'=>'Buzzard');
    $values[] = array('first_name'=>'Victor','last_name'=>'Vulture');
    $values[] = array('first_name'=>'Bill','last_name'=>'Blue Jay');
    $values[] = array('first_name'=>'Bill','last_name'=>'Buzzard');

    $result = search_for($values,$args);
    var_dump($result);exit;

    function     search_for($array,$args) {
    $results = array();
    foreach (    $array as $row) {
    $found = false;
    $hits = array();
    foreach (    $row as $k => $v) {
    if (    array_key_exists($k,$args)) $hits[$k] = ($args[$k] == $v);
    }

    $found = array_product($hits);
    if (!    in_array($row,$results) && true == $found) $results[] = $row;
    }

    return     $results;
    }
    ?>

    Output:

    array (size=1)
    0 =>
    array (size=2)
    'first_name' => string 'Bill' (length=4)
    'last_name' => string 'Buzzard' (length=7)
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