php数组合并：array_merge与操作符加+的区别

$a = array(
 'a' =>10,
 'b' => 11,
);

$c = array(
 'a' =>12,
 'd' => 19
 );

print_r($a+$c);

print_r(array_merge($a,$c));

上面代码输出：

</pre>
Array
(
 [a] => 10
 [b] => 11
 [d] => 19
)
Array
(
 [a] => 12
 [b] => 11
 [d] => 19
)
<pre>

结论：加号是不覆盖的合并，array_merge合并时相同key会覆盖。