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# count

(PHP 3, PHP 4 , PHP 5)

count -- Count elements in a variable

## Description

int count ( mixed var [, int mode])

Returns the number of elements in var, which is typically an array (since anything else will have one element).

If var is not an array, 1 will be returned (exception: count(`NULL`) equals 0).

> 備注: The optional mode parameter is available as of PHP 4.2.0.

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. The default value for mode is 0.

小心!
count() may return 0 for a variable that isn't set, but it may also return 0 for a variable that has been initialized with an empty array. Use isset() to test if a variable is set.

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

示範 1.count() example
`<?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; ?>`

示範 2. recursive count() example (PHP >= 4.2.0)
`<?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 ?>`

> 備注: The sizeof() function is an alias for count().

See also is_array(), isset(), and strlen().

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