$arr = array(
'key1' => 'value1',
'key2' => 'value2
);
$a = array(
'key3' => 'value3'
);
$arr = $arr + $a;
$arr['key3'] = 'value3';
$arr = array(
'key1' => 'value1',
'key2' => 'value2
);
$a = array(
'key3' => 'value3'
);
$arr = $arr + $a;
$arr['key3'] = 'value3';