array_keys() Function
The array_keys() function is used to return all the keys or a subset of the array keys. This function works for both indexed as well as associative arrays.
Syntax
array_keys(array, value, strict);
Parameters
- array: An array with keys to check.
- value: The value to retrieve the keys for.
- strict: The parameter to check the data type of the variable or not.
Example 1: This example illustrates the basic usage of the array_keys() Function in PHP.
PHP
<?php$arr = array( "Java" => "SpringBoot", "PHP 4.0" => "CodeIgniter", "Python" => "Django", "PHP 3.0" => "CodeIgniter");// Searching for keys of codeigniter$key1 = array_keys($arr, "CodeIgniter");print("Keys for CodeIgniter : ");print_r($key1);print("</br>");// Searching for keys of wordpress$key2 = array_keys($arr, "WordPress");print("Keys for WordPress : ");print_r($key2);?> |
Output:
Keys for CodeIgniter : Array ( [0] => PHP 4.0 [1] => PHP 3.0 )
Keys for WordPress : Array ( )
Example 2: This is another example that illustrates the basic usage of the array_keys() Function in PHP.
PHP
<?php$arr = array(1, 2, 3, 4, 5);// Searching for keys of string 5// using strict parameter true$key1 = array_keys($arr, "5", true);print ("Keys for '5' : ");print_r($key1);echo ("</br>");// Searching for keys of string 5// using strict parameter false$key2 = array_keys($arr, "5", false);print ("Keys for '5' : ");print_r($key2);?> |
Output:
Keys for '5' : Array ( )
Keys for '5' : Array ( [0] => 4 )
What are the differences between array_keys() and array_key_exists() in PHP ?
The following article indicates the differences between the two inbuilt functions array_keys() and array_key_exists() in PHP.