count

(PHP 4, PHP 5, PHP 7)

countCompte tous les éléments d'un tableau ou quelque chose d'un objet

Description

count ( mixed $array_or_countable [, int $mode = COUNT_NORMAL ] ) : int

Compte tous les éléments d'un tableau ou quelque chose d'un objet.

Pour les objets, count() retourne le nombre de propriétés non-statiques, sans tenir compte de la visibilité. Si SPL est disponible, vous pouvez utiliser la fonction count() en implémentant l'interface Countable. Cette interface a exactement une méthode, Countable::count(), qui retourne la valeur retournée par la fonction count().

Reportez-vous à la section sur les Tableaux du manuel, pour plus de détails sur le fonctionnement des tableaux en PHP.

Liste de paramètres

array_or_countable

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 array_or_countable. Quand le paramètre n'est ni un objet, ni un tableau qui implémente l'interface Countable, 1 sera retourné. Il y a néanmoins une exception : si le paramètre array_or_countable vaut NULL, 0 sera retourné.

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));

var_dump(count(null));

var_dump(count(false));
?>

L'exemple ci-dessus va afficher :

int(3)
int(3)

Warning: count(): Parameter must be an array or an object that implements Countable in … on line 12 // as of PHP 7.2
int(0)

Warning: count(): Parameter must be an array or an object that implements Countable in … on line 14 // as of PHP 7.2
int(1)

Exemple #2 Exemple de récursivité avec count()

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

// count récursif
echo count($foodCOUNT_RECURSIVE); // affiche 8

// count normal
echo count($food); // affiche 2

?>

Historique

Version Description
7.2.0 count() va maintenant générer un avertissement sur des types dénombrables non valides sont passés au paramètre array_or_countable.

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

add a note add a note

User Contributed Notes 14 notes

up
107
onlyranga at gmail dot com
5 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
5
jerome dot gds at gmail dot com
1 month ago
to end the debate: count() is the same as empty()

test code below:

results on my computer:

count : double(0.81396999359131)
empty : double(0.81621310710907)

using isset($test[0]) is a bit slower than empty;
test without adding value to the array in function ****Test: still the same.

<?php

function average(array $test)
{
   
$sum = 0;
    foreach(
$test as $value) {
       
$sum += $value;
    }

    return
$sum;
}

function
countTest(array $test)
{
   
$i = 0;
    while (
$i++ < 1000000) {
       
count($test);
       
$test["lol$i"] = "teset$i";
    }
}

function
emptyTest(array $test)
{
   
$i = 0;
    while (
$i++ < 1000000) {
        empty(
$test);
       
$test["lol$i"] = "teset$i";
    }
}

$test = [];
$i = 0;
while (
$i++ < 20000000) {
   
$test[] = $i;
}

$j = 10;
$value = $j;
$count = [];
$isEmpty = [];
while (
$j--) {
   
$time = microtime(true);
   
countTest($test);
   
$count[] = microtime(true) - $time;

   
$time = microtime(true);
   
emptyTest($test);
   
$isEmpty[] = microtime(true) - $time;
}

var_dump(average($count) / $value);
var_dump(average($isEmpty) / $value);
up
6
lucasfsmartins at gmail dot com
8 months 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
23
alexandr at vladykin dot pp dot ru
13 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
7
buyatv at gmail dot com
2 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
14
danny at dannymendel dot com
12 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
php_count at cubmd dot com
2 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
4
pied-pierre
4 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
0
Anonymous
1 month 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
2
Gerd Christian Kunze
5 years ago
Get maxWidth and maxHeight of a two dimensional array..?

Note:
1st dimension = Y (height)
2nd dimension = X (width)
e.g. rows and cols in database result arrays

<?php
$TwoDimensionalArray
= array( 0 => array( 'key' => 'value', ...), ... );
?>

So for Y (maxHeight)
<?php
$maxHeight
= count( $TwoDimensionalArray )
?>

And for X (maxWidth)
<?php
$maxWidth
= max( array_map( 'count'$TwoDimensionalArray ) );
?>

Simple? ;-)
up
-3
JumpIfBelow
4 years ago
As I see in many codes, don't use count to iterate through array.
Onlyranga says you could declare a variable to store it before the for loop.
I agree with his/her approach, using count in the test should be used ONLY if you have to count the size of the array for each loop.

You can do it in the for loop too, so you don't have to "search" where the variable is set.
e.g.
<?php
    $array
= [1, 5, 'element'];
    for(
$i = 0, $c = count($array); $i < $c; $i++)
       
var_dump($array[$i]);
?>
up
-11
buyatv at gmail dot com
2 years ago
You can not get collect sub array count when use the key on only one sub array in an array:

$a = array("a"=>"appple", b"=>array('a'=>array(1,2,3),'b'=>array(1,2,3)));
$b = array("a"=>"appple", "b"=>array(array('a'=>array(1,2,3),'b'=>array(1,2,3)), array(1,2,3),'b'=>array(1,2,3)), array('a'=>array(1,2,3),'b'=>array(1,2,3))));

echo count($a['b']);  // 2 NOT 1, expect 1
echo count($b['b']);  // 3,   expected
up
-18
ThisIsNotImportant
3 years ago
About 2d arrays, you have many way to count elements :

<?php
$MyArray
= array ( array(1,2,3),
                  
1,
                  
'a',
                   array(
'a','b','c','d') );

// All elements
echo count($MyArray ,COUNT_RECURSIVE);  // output 11 (9 values + 2 arrays)

// First level elements
echo count($MyArray );                  // output 4 (2 values+ 2 arrays)

// Both level values, but only values
echo(array_sum(array_map('count',$MyArray ))); //output 9 (9 values)

// Only second level values
echo (count($MyArray ,COUNT_RECURSIVE)-count($MyArray )); //output 7 ((all elements) - (first elements))
?>
up
-4
flavioaugusto dot br at gmail dot com
8 months ago
Criada para contar quantos níveis um array multidimensional possui.

function count_multiLevel($matrix, $_LEVEL = 0){
       
        /* Variáveis de recursão */
        $_COUNT = $_LEVEL;
       
        /* Verifica se o ARRAY foi instanciado */
        if (is_setVar($matrix)){
           
            /* Verifica se a variável é um ARRAY */
            if(is_array($matrix)){
               
                /* Loop de elementos da matriz*/
                foreach ($matrix as $elements => $value) {
                   
                    /* Auxiliar para verificação posterior */
                    $_AUX = $_COUNT;
                   
                    /* Verifiando os Nós */
                    if (is_array($matrix[$elements])) {
                        $_COUNT = count_multiLevel($matrix[$elements], $_LEVEL+1);   
                    }
                    /* Cereja do bolo */
                    if($_AUX > $_COUNT)
                        $_COUNT = $_AUX;
                }
                /* Retorn do resultado da operação */
                return $_COUNT;
               
            }else{
                /* Em casos que o valor passado não seja uma matriz/array */
                return -1;
            }
        }
    }
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