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count

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(PHP 4, PHP 5, PHP 7)

count — Count all elements in an array, or something in an object

Description

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

Counts all elements in an array, or something in an object.

For objects, if you have SPL installed, you can hook into count() by implementing interface Countable. The interface has exactly one method, Countable::count(), which returns the return value for the count() function.

Please see the Array section of the manual for a detailed explanation of how arrays are implemented and used in PHP.

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Parameters

array_or_countable

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.

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Return Values

Returns the number of elements in array_or_countable. When the parameter is neither an array nor an object with implemented Countable interface, 1 will be returned. There is one exception, if array_or_countable is NULL, 0 will be returned.

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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));

var_dump(count(null));

var_dump(count(false));
?>

The above example will output:

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)

Example #2 Recursive count() example

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

// recursive count
echo count($food, COUNT_RECURSIVE); // output 8

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

?>

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Changelog

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

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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

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Document created the 30/01/2003, last modified the 26/10/2018
Source of the printed document:https://www.gaudry.be/en/php-rf-function.count.html

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References

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