How to merge arrays and preserve the keys in PHP ?
Arrays in PHP are created using array() function. Arrays are variable that can hold more than one values at a time. There are three types of arrays:
- Indexed Arrays
- Associative Arrays
- Multidimensional Arrays
Each and every value in an array has a name or identity attached to it used to access that element called keys.
To merge the two arrays array_merge() function works fine but it does not preserve the keys. Instead array_replace() function helps to merge two arrays while preserving their key.
Program 1: This example using array_replace() function to merge two arrays and preserve the keys.
<?php   // Create first associative array $array1 = array(     1 => 'Welcome',     2 => 'To');   // Create second associative array $array2 = array(     3 => 'Geeks',     4 => 'For',     5 => 'Geeks');   // Use array_replace() function to // merge the two array while // preserving the keys print_r(array_replace($array1, $array2)); ?> |
Output:
Array
(
[1] => Welcome
[2] => To
[3] => Geeks
[4] => For
[5] => Geeks
)
Program 1: This example using array_replace_recursive() function to merge two arrays and preserve the keys.
<?php   // Create first associative array $array1 = array(     1 => 'Welcome',     2 => 'To');   // Create second associative array $array2 = array(     3 => 'Geeks',     4 => 'For',     5 => 'Geeks');   // Use array_replace() function to // merge the two array while // preserving the keys print_r(array_replace_recursive($array1, $array2)); ?> |
Output:
Array
(
[1] => Welcome
[2] => To
[3] => Geeks
[4] => For
[5] => Geeks
)
