key-value toevoegen aan array

$hashmap = array(...);
...
array_push($hashmap, $key => $value);

$hashmap = array(...);
...
array_push($hashmap, $key => $value);

$hashmap[$key] = $value;

$hashmap[$key] = $value;

$hashmap[]=$key => $value;

$hashmap[]=$key => $value;