在php中可以使用array_merge函数和两个数组相加array+array的方式进行数组合并，但两者效果并不相同，下面为大家介绍两者具体的使用区别.
区别如下：
当下标为数值时，array_merge()不会覆盖掉原来的值，但array＋array合并数组则会把最先出现的值作为最终结果返回，而把后面的数组拥有相同键名的那些值“抛弃”掉（不是覆盖）.
当下标为字符时，array＋array仍然把最先出现的值作为最终结果返回，而把后面的数组拥有相同键名的那些值“抛弃”掉，但array_merge()此时会覆盖掉前面相同键名的值.
例子1:
代码：
$arr1 = [‘PHP‘, ‘apache‘];
$arr2 = [‘PHP‘, ‘mysql‘, ‘html‘, ‘CSS‘];
$mergeArr = array_merge($arr1, $arr2);
$plusArr = $arr1 + $arr2;
var_dump($mergeArr);
var_dump($plusArr);
结果
$mergeArr：
array (size=6)
0 => string ‘PHP‘ (length=3)
1 => string ‘apache‘ (length=5)
2 => string ‘PHP‘ (length=3)
3 => string ‘MySQl‘ (length=5)
4 => string ‘HTML‘ (length=4)
5 => string ‘CSS‘ (length=3)
$plusArr
array (size=4)
0 => string ‘PHP‘ (length=3)
1 => string ‘apache‘ (length=5)
2 => string ‘HTML‘ (length=4)
3 => string ‘CSS‘ (length=3
例子2:
代码：
$arr1 = [‘PHP‘, ‘a‘=>‘MySQl‘];
$arr2 = [‘PHP‘, ‘MySQl‘, ‘a‘=>‘HTML‘, ‘CSS‘];
$mergeArr = array_merge($arr1, $arr2);
$plusArr = $arr1 + $arr2;
var_dump($mergeArr);
var_dump($plusArr);
结果
$mergeArr:
array (size=5)
0 => string ‘PHP‘ (length=3)
‘a‘ => string ‘HTML‘ (length=4)
1 => string ‘PHP‘ (length=3)
2 => string ‘MySQl‘ (length=5)
3 => string ‘CSS‘ (length=3)
$plusArr
array (size=4)
0 => string ‘PHP‘ (length=3)
‘a‘ => string ‘MySQl‘ (length=5)
1 => string ‘MySQl‘ (length=5)
2 => string ‘CSS‘ (length=3)
例子3:
代码:
$arr1 = [‘PHP‘, ‘a‘=>‘MySQl‘,‘6‘=>‘CSS‘];
$arr2 = [‘PHP‘, ‘MySQl‘, ‘a‘=>‘HTML‘, ‘CSS‘];
$mergeArr = array_merge($arr1, $arr2);
$plusArr = $arr1 + $arr2;
var_dump($mergeArr);
var_dump($plusArr);
结果:
$mergeArr
array (size=6)
0 => string ‘PHP‘ (length=3)
‘a‘ => string ‘HTML‘ (length=4)
1 => string ‘CSS‘ (length=3)
2 => string ‘PHP‘ (length=3)
3 => string ‘MySQl‘ (length=5)
4 => string ‘CSS‘ (length=3)
$plusArr
array (size=5)
0 => string ‘PHP‘ (length=3)
‘a‘ => string ‘MySQl‘ (length=5)
6 => string ‘CSS‘ (length=3)
1 => string ‘MySQl‘ (length=5)
2 => string ‘CSS‘ (length=3)