array_merge VS plus

gistfile1.php

<?php

$ary1 = array(
	'matsu' => 'ary1 matsu',
	'take' => 'ary1 take',
	'ume' => 'ary1 ume', 
	'ary1' => 'ary1 value', 
);


$ary2 = array(
	'matsu' => 'ary2 matsu',
	'take' => 'ary2 take',
	'ume' => 'ary2 ume', 
	'ary2' => 'ary2 value', 
);


print_r (array_merge($ary1, $ary2));

print_r ($ary1 + $ary2);

/*
output:
Array
(
    [matsu] => ary2 matsu
    [take] => ary2 take
    [ume] => ary2 ume
    [ary1] => ary1 value
    [ary2] => ary2 value
)
Array
(
    [matsu] => ary1 matsu
    [take] => ary1 take
    [ume] => ary1 ume
    [ary1] => ary1 value
    [ary2] => ary2 value
)
*/