count

    (PHP 4, PHP 5, PHP 7, PHP 8)

    count — Compte tous les éléments d'un tableau ou dans un objet Countable

    Description

    count(Countable|array $value, int $mode = COUNT_NORMAL): int

    Compte tous les éléments dans un tableau quand utilisé avec un tableau. Quand utilisé avec un objet qui implémente l'interface Countable, ceci retourne la valeur de la méthode Countable::count().

    Liste de paramètres

    value

    Un tableau ou un objet Countable.

    mode

    Si le paramètre optionnel mode vaut COUNT_RECURSIVE (ou 1), count() va compter récursivement les tableaux. C'est particulièrement pratique pour compter le nombre d'éléments d'un tableau.

    Attention

    La fonction count() peut détecter les récursions afin d'éviter les boucles infinies, mais émettra une alerte de type E_WARNING à chaque fois qu'une boucle infinie surviendra (dans le cas où un tableau contient lui-même plus d'une boucle infinie) et retournera un compteur plus grand que l'attendu.

    Valeurs de retour

    Retourne le nombre d'éléments dans value. Antérieur à PHP 8.0.0, si le paramètre n'est ni un tableau, ni un objet qui implémente l'interface Countable, 1 était retourné, sauf si value était null, au quel cas 0 était retourné.

    Historique

    Version Description
    8.0.0 count() lance désormais une TypeError pour des types dénombrables invalides passés au paramètre value.
    7.2.0 count() génère désormais un avertissement pour des types dénombrables invalides passés au paramètre value.

    Exemples

    Exemple #1 Exemple avec count()

    <?php
    $a    [0] = 1;
    $a[1] = 3;
    $a[2] = 5;
    var_dump(count($a));

    $b[0] = 7;
    $b[5] = 9;
    $b[10] = 11;
    var_dump(count($b));
    ?>

    L'exemple ci-dessus va afficher :

    int(3)
int(3)

    Exemple #2 Exemple de count() avec un argument non Countable|array (contre-exemple - ne pas faire ceci)

    <?php
    $b    [0] = 7;
    $b[5] = 9;
    $b[10] = 11;
    var_dump(count($b));

    var_dump(count(null));

    var_dump(count(false));
    ?>

    L'exemple ci-dessus va afficher :

    int(3)
int(0)
int(1)

    Résultat de l'exemple ci-dessus en PHP 7.2:

    int(3)

Warning: count(): Parameter must be an array or an object that implements Countable in … on line 12
int(0)

Warning: count(): Parameter must be an array or an object that implements Countable in … on line 14
int(1)

    Résultat de l'exemple ci-dessus en PHP 8 :

    int(3)

Fatal error: Uncaught TypeError: count(): Argument #1 ($var) must be of type Countable .. on line 12

    Exemple #3 Exemple de récursivité avec count()

    <?php
    $food     = array('fruits' => array('orange', 'banana', 'apple'),
    'veggie' => array('carrot', 'collard', 'pea'));

    // count récursif
    var_dump(count($food, COUNT_RECURSIVE));

    // count normal
    var_dump(count($food));

    ?>

    L'exemple ci-dessus va afficher :

    int(8)
int(2)

    Exemple #4 Objet Countable

    <?php
    class CountOfMethods implements Countable
    {
    private function     someMethod()
    {
    }
    public function     count(): int
    {
    return     count(get_class_methods($this));
    }
    }
    $obj = new CountOfMethods();
    var_dump(count($obj));
    ?>

    L'exemple ci-dessus va afficher :

    int(2)

    Voir aussi

    • is_array() - Détermine si une variable est un tableau
    • isset() - Détermine si une variable est déclarée et est différente de null
    • empty() - Détermine si une variable est vide
    • strlen() - Calcule la taille d'une chaîne
    • is_countable() - Vérifie si le contenu de la variable est une valeur dénombrable
    • Les tableaux

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    User Contributed Notes 13 notes

    up
    141
    onlyranga at gmail dot com
    10 years ago
    [Editor's note: array at from dot pl had pointed out that count() is a cheap operation; however, there's still the function call overhead.]

    If you want to run through large arrays don't use count() function in the loops , its a over head in performance, copy the count() value into a variable and use that value in loops for a better performance.

    Eg:

    // Bad approach

    for($i=0;$i<count($some_arr);$i++)
    {
    // calculations
    }

    // Good approach

    $arr_length = count($some_arr);
    for($i=0;$i<$arr_length;$i++)
    {
    // calculations
    }
    up
    4
    lucasfsmartins at gmail dot com
    5 years ago
    If you are on PHP 7.2+, you need to be aware of "Changelog" and use something like this:

    <?php
    $countFruits     = is_array($countFruits) || $countFruits instanceof Countable ? count($countFruits) : 0;
    ?>

    You can organize your code to ensure that the variable is an array, or you can extend the Countable so that you don't have to do this check.
    up
    3
    Anonymous
    5 years ago
    For a Non Countable Objects

    $count = count($data);
    print "Count: $count\n";

    Warning: count(): Parameter must be an array or an object that implements Countable in example.php on line 159

    #Quick fix is to just cast the non-countable object as an array..

    $count = count((array) $data);
    print "Count: $count\n";

    Count: 250
    up
    13
    danny at dannymendel dot com
    17 years ago
    I actually find the following function more useful when it comes to multidimension arrays when you do not want all levels of the array tree.

    // $limit is set to the number of recursions
    <?php
    function count_recursive ($array, $limit) {
    $count = 0;
    foreach (    $array as $id => $_array) {
    if (    is_array ($_array) && $limit > 0) {
    $count += count_recursive ($_array, $limit - 1);
    } else {
    $count += 1;
    }
    }
    return     $count;
    }
    ?>
    up
    4
    pied-pierre
    9 years ago
    A function of one line to find the number of elements that are not arrays, recursively :

    function count_elt($array, &$count=0){
    foreach($array as $v) if(is_array($v)) count_elt($v,$count); else ++$count;
    return $count;
    }
    up
    9
    alexandr at vladykin dot pp dot ru
    18 years ago
    My function returns the number of elements in array for multidimensional arrays subject to depth of array. (Almost COUNT_RECURSIVE, but you can point on which depth you want to plunge).

    <?php
    function getArrCount ($arr, $depth=1) {
    if (!    is_array($arr) || !$depth) return 0;

    $res=count($arr);

    foreach (    $arr as $in_ar)
    $res+=getArrCount($in_ar, $depth-1);

    return     $res;
    }
    ?>
    up
    0
    olja dot fb at gmail dot com
    1 year ago
    In example #3, given as:

    <?php
    $food     = array('fruits' => array('orange', 'banana', 'apple'),
    'veggie' => array('carrot', 'collard', 'pea'));

    // recursive count
    var_dump(count($food, COUNT_RECURSIVE));
    ?>

    with the output given as int(8), it may have some readers mistaken, as I was at first: one might take it as keys being counted as well as the inner array entries:

    <?php
    // NO:
    'fruits', 'orange', 'banana', 'apple',
    'veggie', 'carrot', 'collard', 'pea'
    ?>

    But actually keys are not counted in count function, and why it is still 8 - because inner arrays are counted as entries as well as their inner elements:

    <?php
    // YES:
    array('orange', 'banana', 'apple'), 'orange', 'banana', 'apple',
    array(    'carrot', 'collard', 'pea'), 'carrot', 'collard', 'pea'
    ?>
    up
    -1
    php_count at cubmd dot com
    7 years ago
    All the previous recursive count solutions with $depth option would not avoid infinite loops in case the array contains itself more than once.
    Here's a working solution:

    <?php
    /**
    * Recursively count elements in an array. Behaves exactly the same as native
    * count() function with the $depth option. Meaning it will also add +1 to the
    * total count, for the parent element, and not only counting its children.
    * @param $arr
    * @param int $depth
    * @param int $i (internal)
    * @return int
    */
    public static function countRecursive(&$arr, $depth = 0, $i = 0) {
    $i++;
    /**
    * In case the depth is 0, use the native count function
    */
    if (empty($depth)) {
    return     count($arr, COUNT_RECURSIVE);
    }
    $count = 0;
    /**
    * This can occur only the first time when the method is called and $arr is not an array
    */
    if (!is_array($arr)) {
    return     count($arr);
    }

    // if this key is present, it means you already walked this array
    if (isset($arr['__been_here'])) {
    return     0;
    }

    $arr['__been_here'] = true;

    foreach (    $arr as $key => &$value) {
    if (    $key !== '__been_here') {
    if (    is_array($value) && $depth > $i) {
    $count += self::countRecursive($value, $depth, $i);
    }

    $count++;
    }
    }

    // you need to unset it when done because you're working with a reference...
    unset($arr['__been_here']);
    return     $count;
    }
    ?>
    up
    -1
    asma mechtaba
    2 years ago
    count and sizeof are aliases, what work for one works for the other.
    up
    -2
    Christoph097
    2 years ago
    Empty values are counted:
    <?php
    $ar    [] = 3;
    $ar[] = null;
    var_dump(count($ar)); //int(2)
    ?>
    up
    -5
    buyatv at gmail dot com
    7 years ago
    You can not get collect sub array count when there is only one sub array in an array:

    $a = array ( array ('a','b','c','d'));
    $b = array ( array ('a','b','c','d'), array ('e','f','g','h'));

    echo count($a); // 4 NOT 1, expect 1
    echo count($b); // 2, expected
    up
    -5
    vojtaripa at gmail dot com
    4 years ago
    To get the count of the inner array you can do something like:

    $inner_count = count($array[0]);
    echo ($inner_count);
    up
    -4
    max at schimmelmann dot org
    4 years ago
    In special situations you might only want to count the first level of the array to figure out how many entries you have, when they have N more key-value-pairs.

    <?php

    $data     = [
    'a' => [
    'bla1' => [
    0 => 'asdf',
    1 => 'asdf',
    2 => 'asdf',
    ],
    'bla2' => [
    0 => 'asdf',
    1 => 'asdf',
    2 => 'asdf',
    ],
    'bla3' => [
    0 => 'asdf',
    1 => 'asdf',
    2 => 'asdf',
    ],
    'bla4' => [
    0 => 'asdf',
    1 => 'asdf',
    2 => 'asdf',
    ],
    ],
    'b' => [
    'bla1' => [
    0 => 'asdf',
    1 => 'asdf',
    2 => 'asdf',
    ],
    'bla2' => [
    0 => 'asdf',
    1 => 'asdf',
    2 => 'asdf',
    ],
    ],
    'c' => [
    'bla1' => [
    0 => 'asdf',
    1 => 'asdf',
    2 => 'asdf',
    ]
    ]
    ];
    $count = array_sum(array_values(array_map('count', $data)));
    // will return int(7)
    var_dump($count);

    // will return 31
    var_dump(count($data, 1));
    ?>
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