how does php array merge work code example

Example 1: php array_merge

<?php
$array1 = array("color" => "red", 2, 4);
$array2 = array("a", "b", "color" => "green", "shape" => "trapezoid", 4);
$result = array_merge($array1, $array2);
print_r($result);
?>
Array
(
    [color] => green
    [0] => 2
    [1] => 4
    [2] => a
    [3] => b
    [shape] => trapezoid
    [4] => 4
)

Example 2: php array merge for associative arrays

<?php

$array1 = array('key1' => 'test1', 'key2' => 'test2');
$array2 = array('key3' => 'test3', 'key4' => 'test4');

$resultArray = array_merge($array1, $array2);

// If you have numeric or numeric like keys, array_merge will 
// reset the keys to 0 and start numbering from there

$resultArray = $array1 + $array2;

// Using the addition operator will allow you to preserve your keys,
// however any duplicate keys will be ignored.