<?php
$apples = [ 'red' => 'π', 'green' => 'π' ];
$others = [ 'green' => 'π', 'pink' => 'π' ];
$fruits = [ ...$apples, ...$others ];
var_dump( $fruits );
?>
array(3) {
'red' => string(4) "π"
'green' => string(4) "π"
'pink' => string(4) "π"
}