PHP array_key_exists() function usage and example

PHP Array Function Manual

The PHP array_key_exists() function checks if there is a specified key name or index in the array

Syntax

bool array_key_exists ($key, $array);

Definition and Usage

When the key key exists in the array ($array), array_key_exists() returns TRUE.

Parameter

Return value

If the given key exists in the array, it returns TRUE, otherwise it returns FALSE.

Online Example

<?php
　　　$input = array('first' =>　10, 'second' =>　400);
　　　
　　　if (array_key_exists('first', $input)) {
　　　　　　echo "The first element exists in the array";
　　　}
?>

Output result:

The first element exists in the array

PHP Array Function Manual