find the union of two maps in php

To find the union of two maps in PHP, we can use the array_merge() function. This function takes two or more arrays as arguments and returns a new array that contains all the elements from the input arrays.

To merge two maps, simply pass them as arguments to array_merge(). However, if both maps have the same key, only the value from the last map will be included in the merged array.

Here's an example:

main.php
$map1 = array('a' => 1, 'b' => 2, 'c' => 3);
$map2 = array('c' => 4, 'd' => 5, 'e' => 6);

$merged = array_merge($map1, $map2);

print_r($merged);
147 chars
7 lines

The output will be:

main.php
Array
(
    [a] => 1
    [b] => 2
    [c] => 4
    [d] => 5
    [e] => 6
)
75 chars
9 lines

In this example, the keys 'a', 'b', and 'c' are in $map1, and the keys 'c', 'd', and 'e' are in $map2. After merging the two maps, the resulting array includes all six key/value pairs. The value for 'c' in $map2 replaces the value in $map1.