PHP: key() function
PHP: Fetch a key from an array
The key() function is used to get the index element of the current array position.
Version:
(PHP 4 and above)
Syntax:
key(array_name)
Parameter:
Name | Description | Required / Optional |
Type |
---|---|---|---|
array_name | Array to use. | Required | Array |
Return value:
The key of the current array element
Value Type : Mixed*.
*Mixed : Mixed indicates that a parameter may accept multiple (but not necessarily all) types.
Example:
<?php
$subjects = array("Subject1" => "Physics", "Subject2" => "Chemistry", "Subject3" => "Biology");
echo "Current position Key is : " . key($subjects);
?>
Output:
Current position Key is: Subject1
Pictorial Presentation:

View the example in the browser
Practice here online:
See also
PHP: Tips of the Day
Filters the collection using the given callback
Example:
<?php function tips_reject($items, $func) { return array_values(array_diff($items, array_filter($items, $func))); } print_r(tips_reject(['Apple', 'Pear', 'Kiwi', 'Banana'], function ($item) { return strlen($item) > 4; })); ?>
Output:
Array ( [0] => Pear [1] => Kiwi )
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