首先來看看鍵名是string，兩者區別：

復制代碼 代碼如下:

<?php
$arr1 = array('a'=>'PHP');
$arr2 = array('a'=>'JAVA');
//如果鍵名為字符，且鍵名相同，array_merge()后面數組元素值會覆蓋前面數組元素值
print_r(array_merge($arr1,$arr2)); //Array ( [a] => JAVA )
//如果鍵名為字符，且鍵名相同，數組相加會將最先出現的值作為結果
print_r($arr1+$arr2); //Array ( [a] => PHP )
?>

復制代碼 代碼如下:

<?php
$arr1 = array("C","PHP");
$arr2 = array("JAVA","PHP");
//如果鍵名為數字，array_merge()不會進行覆蓋
print_r(array_merge($arr1,$arr2));//Array ( [0] => C [1] => PHP [2] => JAVA [3] => PHP )
//如果鍵名為數組，數組相加會將最先出現的值作為結果，后面鍵名相同的會被拋棄
print_r($arr1+$arr2);//Array ( [0] => C [1] => PHP )
?>

復制代碼 代碼如下:

<?php
$arr1 = array("a"=>"php","c");
$arr2 = array("a"=>"java","c","ruby");
print_r(array_merge_recursive($arr1, $arr2));
?>