We have given an array arr and a Key key, the task is to check if a key exists in an array or not in PHP.
Examples:
Input : arr = ["Geek1", "Geek2", "1", "2","3"]
key = "2"
Output : Found the Key
Input : arr = ["Geek1", "Geek2", "1", "2","3"]
key = 9
Output : Key not Found
The problem can be solved using PHP inbuilt function for checking key exists in a given array. The in-built function used for the given problem are:
Method 1: Using array_key_exists() Method: The array_key_exists() function checks whether a specific key or index is present inside an array or not.
Syntax:
boolean array_key_exists( $index, $array )
Example:
PHP
<?php // PHP program to check if a key // exists in an array or not $array = array( 'names' => array("Geek1", "Geek2", "Geek3"), 'rank' => array('1', '2', '3') ); // Use of array_key_exists() function if(array_key_exists("rank", $array)) { echo "Found the Key"; } else{ echo "Key not Found"; } ?> |
Output
Found the Key
Method 2: Using isset() Method: The isset() function checks whether a specific key or index is present inside an array or not.
Syntax:
bool isset( mixed $var, mixed $... )
PHP
<?php // PHP program to check if a key // exists in an array or not $array = array( 'names' => array("Geek1", "Geek2", "Geek3"), 'rank' => array('1', '2', '3') ); // Use of array_key_exists() function if(isset($array["rank"])){ echo "Found the Key"; } else{ echo "Key not Found"; } ?> |
Output
Found the Key
