php一维数组合并的三种方式对比-php手册-php.cn

php一维数组合并的三种方式对比

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Release： 2016-06-06 20:13:47

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php数组合并有三种方式：array_merge,array_merge_recursive,+(就是数学运算符加号); 下面是一段对比的代码 $array1 = array(2,4,"color" = "red"); $array2 = array("a", "b", "color" = "green", "shape" = "trapezoid", 4); $result = array_merge($array

php数组合并有三种方式：array_merge,array_merge_recursive,+(就是数学运算符加号);
下面是一段对比的代码

    $array1 = array(2,4,"color" => "red");
    $array2 = array("a", "b", "color" => "green", "shape" => "trapezoid", 4);
    $result = array_merge($array1, $array2);
    echo "----------------array_merge---------------".PHP_EOL;
    print_r($result);
    echo "----------------+++++++++++---------------".PHP_EOL;
    print_r($array1+$array2);
    echo "----------------array_merge_recursive---------------".PHP_EOL;
    print_r(array_merge_recursive($array1,$array2));

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结果如下所示

----------------array_merge---------------
Array
(
    [0] => 2
    [1] => 4
    [color] => green
    [2] => a
    [3] => b
    [shape] => trapezoid
    [4] => 4
)
----------------+++++++++++---------------
Array
(
    [0] => 2
    [1] => 4
    [color] => red
    [shape] => trapezoid
    [2] => 4
)
----------------array_merge_recursive---------------
Array
(
    [0] => 2
    [1] => 4
    [color] => Array
        (
            [0] => red
            [1] => green
        )
    [2] => a
    [3] => b
    [shape] => trapezoid
    [4] => 4
)

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对比array_merge和+以及array_merge_recursive结果的”color”的值我们可以看出：
1.对于相同的字符串索引，
array_merge则会用后面的值覆盖前面出现的值;
+会用前面出现过的值覆盖后面相同的key;
array_merge_recursive则会把相同的索引放到一个数组里面，增加数组的维度;
2.对于相同的数字索引，
array_merge则会给重复的值重建索引(索引值从0开始);
+仍然是用前面出现过的值覆盖后面的值;
array_merge_recursive和array_merge的处理方法一样。

原文地址：php一维数组合并的三种方式对比, 感谢原作者分享。