PHP function array_merge is nice in that you can easily merge one (or more) arrays into a single array with a single call of the function. The keys are retained, but only if they’re not numeric keys(!).
"hi"); $array2 = array(3 => "data"); $result = array_merge($array1, $array2); ?> Result: Array (  => hi  => data )
Perhaps this is the behavior you want. But what if you want to retain the original numeric keys?
Most PHP developers tend to create a custom (unnecessary) array_merge function that applies simple logic in order to retain numeric keys during the merge, but the solution is quite simple:
"hi"); $array2 = array(3 => "data"); $result = $array1 + $array2; ?> Result: Array (  => hi  => data )
That’s it. By simply using the add operator you effectively get the array_merge result except you retain the numeric keys.