The array_combine() is a PHP built-in function that combines two arrays. It combines the keys of one array with the values of another array.

Syntax of PHP array_conbine() function:

array_combine($keys_array, $values_array)

This array_combine() function accepts two parameters, and both are mandatory. The function gets the key(s) from the first parameter(array) and gets the values from the second parameter(array). Then combine them and return a new array.

Keep in mind the length of both arrays must be the same otherwise, PHP will through a fatal error.

Example: Let’s say we have an array that contains all the user IDs and another array that contains the user name. We want to combine these arrays to make another associative array.

<?php
$ids = [
    100,
    200,
    300,
    400
];

$name = [
    'Md Khan',
    'jhon Smith',
    'Bob Wilson',
    'Rani Sing'
];

$name_email = array_combine($ids,$name);
print_r($name_email);

#Output: 
Array
(
    [100] => Md Khan
    [200] => jhon Smith
    [300] => Bob Wilson
    [400] => Rani Sing
)