PHP 8.4.2 Released!

    count

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

    count — Counts all elements in an array or in a Countable object

    Description

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

    Counts all elements in an array when used with an array. When used with an object that implements the Countable interface, it returns the return value of the method Countable::count().

    Parameters

    value

    An array or Countable object.

    mode

    If the optional mode parameter is set to COUNT_RECURSIVE (or 1), count() will recursively count the array. This is particularly useful for counting all the elements of a multidimensional array.

    Caution

    count() can detect recursion to avoid an infinite loop, but will emit an E_WARNING every time it does (in case the array contains itself more than once) and return a count higher than may be expected.

    Return Values

    Returns the number of elements in value. Prior to PHP 8.0.0, if the parameter was neither an array nor an object that implements the Countable interface, 1 would be returned, unless value was null, in which case 0 would be returned.

    Changelog

    Version Description
    8.0.0 count() will now throw TypeError on invalid countable types passed to the value parameter.
    7.2.0 count() will now yield a warning on invalid countable types passed to the value parameter.

    Examples

    Example #1 count() example

    <?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));
    ?>

    The above example will output:

    int(3)
int(3)

    Example #2 count() non Countable|array example (bad example - don't do this)

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

    var_dump(count(null));

    var_dump(count(false));
    ?>

    The above example will output:

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

    Output of the above example in 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)

    Output of the above example in PHP 8:

    int(3)

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

    Example #3 Recursive count() example

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

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

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

    ?>

    The above example will output:

    int(8)
int(2)

    Example #4 Countable object

    <?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));
    ?>

    The above example will output:

    int(2)

    See Also

    • is_array() - Finds whether a variable is an array
    • isset() - Determine if a variable is declared and is different than null
    • empty() - Determine whether a variable is empty
    • strlen() - Get string length
    • is_countable() - Verify that the contents of a variable is a countable value
    • Arrays

    Found A Problem?

    Learn How To Improve This Page • Submit a Pull Request • Report a Bug
    ＋add a note

    User Contributed Notes 7 notes

    up
    143
    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
    3
    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
    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
    2
    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
    0
    mars at tacks dot com
    11 hours ago
    Perhaps this could help someone :
    <?php
    function array_contains_recursion(array $array): bool {
    $result = false;
    set_error_handler(function (int $a, string $b, string $c, int $d) use (&$result) : bool {
    $result = true;
    return     true;
    });
    $_ = count($array, COUNT_RECURSIVE);
    restore_error_handler();
    return     $result;
    }

    // ...

    $a = [];
    var_dump(array_contains_recursion($a)); // false
    $a[] = &$a;
    var_dump(array_contains_recursion($a)); // true
    up
    3
    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
    7
    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;
    }
    ?>
    ＋add a note
    To Top