count

(PHP 4, PHP 5, PHP 7)

countConta o número de elementos de uma variável, ou propriedades de um objeto

Descrição

count ( mixed $var [, int $mode ] ) : int

Conta os elementos de um array, ou propriedades em um objeto.

Para objetos, se você tem SPL instalada, você pode fazer um gancho na count() implementando a interface Countable. A interface tem exatamente um método, count(), que retorna o valor retornado para função count().

Por favor, veja a sessão Array do manual para uma explicação mais detalhada sobre como os arrays são implementados e utilizados no PHP.

Parâmetros

var

The array.

mode

Se o parâmetro opcional mode for COUNT_RECURSIVE (ou 1), a função count() irá recursivamente contar a matriz. Isto é particularmente util para contar elementos em matriz multidimensional. O valor padrão para mode é 0. count() não detecta infinita recursão.

Valor Retornado

Retorna o número de elementos em var, que normalmente é um array, pois qualquer outra coisa terá somente um elemento.

Se var não for um array ou um objeto, com a interface Countable implementada, 1 será retornado. Há uma exceção, se var é NULL, 0 é retornado.

Cuidado

count() pode retornar 0 para uma variável que não existe, mas também pode retornar 0 para uma variável que tenha sido inicializada como um array vazio. Use isset() para checar se a variável existe.

Changelog

Versão Descrição
4.2.0 O parâmetro opcional mode foi adicionado.

Exemplos

Exemplo #1 Exemplo da função count()

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

$b[0] = 7;
$b[5] = 9;
$b[10] = 11;
$result count($b);
// $result == 3

$result count(null);
// $result == 0

$result count(false);
// $result == 1
?>

Exemplo #2 Uso recursivo da função count()

<?php
$comidas 
= array('frutas'  => array('laranja''banana''maçã'),
'veggie'  => array('cenoura''couve','ervilha'));
// contagem recursiva
echo count($comidasCOUNT_RECURSIVE);  // mostra 8
// contagem normal
echo count($comidas);                   // mostra 2
?>

Veja Também

  • is_array() - Verifica se a variável é um array
  • isset() - Informa se a variável foi iniciada
  • strlen() - Retorna o tamanho de uma string

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User Contributed Notes 16 notes

up
116
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
24
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
1
Anonymous
5 months 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
1
jerome dot gds at gmail dot com
6 months 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);
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5
buyatv at gmail dot com
3 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
php_count at cubmd dot com
3 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
lucasfsmartins at gmail dot com
1 year 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
5
Gerd Christian Kunze
6 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
10
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
-1
XavDeb
2 months ago
If you want to know the sub-array containing the MAX NUMBER of values in a 3 dimensions array, here is a try (maybe not the nicest way, but it works):

function how_big_is_the_biggest_sub ($array)  {
   // we parse the 1st level
   foreach ($array AS $key => $array_lvl2) {
         //within level 2, we count the 3d levels max
            $lvl2_nb = array_map( 'count',  $array_lvl2) ;
            $max_nb = max($lvl2_nb);
         // we store the matching keys, it might be usefull
            $max_key = array_search($max_nb, $lvl2_nb);
            $max_nb_all[$max_key.'|'.$key] = $max_nb;
        }
       // now we want the max from all levels 2, so one more time
        $real_max = max($max_nb_all);
        $real_max_key = array_search($real_max, $max_nb_all);
        list($real_max_key2, $real_max_key1) = explode('|', $real_max_key);
                // preparing result
        $biggest_sub['max'] = $real_max;
        $biggest_sub['key1'] = $real_max_key1;
        $biggest_sub['key2'] = $real_max_key2;
       
        return $biggest_sub;
}
/*
$cat_poids_max['M']['Juniors'][] = 55;
$cat_poids_max['M']['Juniors'][] = 61;
$cat_poids_max['M']['Juniors'][] = 68;
$cat_poids_max['M']['Juniors'][] = 76;
$cat_poids_max['M']['Juniors'][] = 100;

$cat_poids_max['M']['Seniors'][] = 55;
$cat_poids_max['M']['Seniors'][] = 60;
$cat_poids_max['M']['Seniors'][] = 67;
$cat_poids_max['M']['Seniors'][] = 75;
$cat_poids_max['M']['Seniors'][] = 84;
$cat_poids_max['M']['Seniors'][] = 90;
$cat_poids_max['M']['Seniors'][] = 100;
//....
$cat_poids_max['F']['Juniors'][] = 52;
$cat_poids_max['F']['Juniors'][] = 65;
$cat_poids_max['F']['Juniors'][] = 74;
$cat_poids_max['F']['Juniors'][] = 100;

$cat_poids_max['F']['Seniors'][] = 62;
$cat_poids_max['F']['Seniors'][] = 67;
$cat_poids_max['F']['Seniors'][] = 78;
$cat_poids_max['F']['Seniors'][] = 86;
$cat_poids_max['F']['Seniors'][] = 100;
*/
$biggest_sub = how_big_is_the_biggest_sub($cat_poids_max);
echo "<li> ".$biggest_sub['key1']." ==> ".$biggest_sub['key2']." ==> ".$biggest_sub['max']; // displays : M ==> Seniors ==> 7
up
1
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
-8
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
-14
buyatv at gmail dot com
3 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
-21
ThisIsNotImportant
4 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
-1
max at schimmelmann dot org
27 days 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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-5
flavioaugusto dot br at gmail dot com
1 year 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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