w3resource

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:

php function reference: key() function

View the example in the browser

Practice here online:

See also

PHP Function Reference

Previous: in_array
Next: krsort



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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
)