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().
valueAn 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.
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.
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.
| 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.
|
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)