<"content-type:text/html;charset=utf-8");

$x = array("red", "green","orange"); 

$y = array("red","blue","yellow","cyan"); 

$z = $x + $y; // $x 与 $y 的联合

var_dump($z);

"//img.jbzj.com/file_images/article/201901/201901200912141.jpg" alt="" />

可以看出，第二个数组中只有第4个值包含在结果中，因为第二个数组的前三个元素具有和第一个数组元素相同的键。接下来让我们看看数组索引不匹配时数组联合运算符"+"的作用：


<"content-type:text/html;charset=utf-8");

$x = array("a" => "red", "b" => "green"); 

$y = array("c" => "blue", "d" => "yellow"); 

$z = $x + $y; // $x 与 $y 的联合

var_dump($z);

"//img.jbzj.com/file_images/article/201901/201901200912142.jpg" alt="" />

可以看出：数组运算符“+”没有对结果中索引进行重新排序。
使用array_merge()函数
array_merge()函数可以用于将两个或多个数组合并为一个数组，例：


<"content-type:text/html;charset=utf-8");

$x = array("0" => "red", "1" => "green","2" => "yellow"); 

$y = array("3" => "blue", "2" => "yellow","1" => " orange"); 

$z = array_merge($x, $y); // $x 与 $y 的联合

var_dump($z);

"//img.jbzj.com/file_images/article/201901/201901200912143.jpg" alt="" />

可以看出，array_merge()函数传递给数组键的数字索引在返回的数组中从零开始重新编号。
使用array_merge_recursive()函数
array_merge_recursive()函数可以把一个或多个数组合并为一个数组。


<"content-type:text/html;charset=utf-8");

$x = array("0" => "red", "1" => "green","2" => "yellow"); 

$y = array("3" => "blue", "2" => "yellow","1" => " orange"); 

$z = array_merge_recursive($x, $y); // $x 与 $y 的联合

var_dump($z);

"//img.jbzj.com/file_images/article/201901/201901200912144.jpg" alt="" />


                                
                                

                                    PHP,合并数组