php中数组合并array_merge 与 + 区别

区别

示例

$a1 = ['a'=>1,'b'=>2];
$a2 = ['a'=>100,'c'=>3];
$a3 = array_merge($a1,$a2);
//输出 ['a'=>100,'b'=>2,'c'=>3]

$a4 = $a1+$a2;
//输出 ['a'=>1,'b'=>2,'c'=>3]