PHP Manual: Counts all elements in an array or in a Countable object

Description

int count(Countablearray $value, int $mode = COUNT_NORMAL)

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)

count

Description

Parameters

Return Values

Changelog

Examples

See Also