PHP中array_merge函數與array+array的區別
在PHP中可以使用array_merge函數和兩個數組相加array+array的方式進行數組合並,但兩者效果並不相同,下面為大家介紹兩者具體的使用區別.
區別如下:
當下標為數值時,array_merge()不會覆蓋掉原來的值,但array+array合並數組則會把最先出現的值作為最終結果返回,而把後面的數組擁有相同鍵名的那些值“拋棄”掉(不是覆蓋).
當下標為字符時,array+array仍然把最先出現的值作為最終結果返回,而把後面的數組擁有相同鍵名的那些值“拋棄”掉,但array_merge()此時會覆蓋掉前面相同鍵名的值.
例子1:
代碼:
$arr1 = [‘PHP‘, ‘apache‘];
$arr2 = [‘PHP‘, ‘MySQl‘, ‘HTML‘, ‘CSS‘];
$mergeArr = array_merge($arr1, $arr2);
$plusArr = $arr1 + $arr2;
var_dump($mergeArr);
var_dump($plusArr);
結果
$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:
代碼:
$arr1 = [‘PHP‘, ‘a‘=>‘MySQl‘];
$arr2 = [‘PHP‘, ‘MySQl‘, ‘a‘=>‘HTML‘, ‘CSS‘];
$mergeArr = array_merge($arr1, $arr2);
$plusArr = $arr1 + $arr2;
var_dump($mergeArr);
var_dump($plusArr);
結果
$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:
代碼:
$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);
結果:
$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)
PHP中array_merge函數與array+array的區別