Question

我有两个数组：

$a = [
    0 => [
        'price' => 5.5
    ],
    1 => [
        'price' => 6.0
    ],
    2 => [
        'price' => 6.2
    ],
    3 => [
        'price' => 6.5
    ],
];

$b = [
    0 => [
        'color' => 'RED'
    ],
    1 => [
        'color' => 'WHITE'
    ],
    2 => [
        'color' => 'BLUE'
    ],
    3 => [
        'color' => 'RED'
    ],
];

我应该有这样的回应：

Array
(
    [0] => Array
        (
            [price] => 5.5
            [color] => RED
        )
    [1] => Array
        (
            [price] => 6
            [color] => WHITE
        )
    [2] => Array
        (
            [price] => 6.2
            [color] => BLUE
        )
    [3] => Array
        (
            [price] => 6.5
            [color] => RED
        )
)

我听说过函数：array_merge_recursive但响应并不是必须的：

Array
(
    [0] => Array
        (
            [price] => 5.5
        )
    [1] => Array
        (
            [price] => 6
        )
    [2] => Array
        (
            [price] => 6.2
        )
    [3] => Array
        (
            [price] => 6.5
        )
    [4] => Array
        (
            [color] => RED
        )
    [5] => Array
        (
            [color] => WHITE
        )

    [6] => Array
        (
            [color] => BLUE
        )
    [7] => Array
        (
            [color] => RED
        )
    )

所以我决定编写自己的函数：

function merge ($a, $b) {
    $keys = array_keys($a);
    foreach ($keys as $value) {
        if (isset($b[$value])) {
            $tmp = array_keys($b[$value]);
            foreach ($tmp as $val){
                $a[$value][$val] = $b[$value][$val];
            }
        }
    }
    return $a;
}
print_r(merge($a, $b));

我得到了正确的答复：

Array
(
    [0] => Array
        (
            [price] => 5.5
            [color] => RED
        )
    [1] => Array
        (
            [price] => 6
            [color] => WHITE
        )
    [2] => Array
        (
            [price] => 6.2
            [color] => BLUE
        )
    [3] => Array
        (
            [price] => 6.5
            [color] => RED
        )
)

问题是它适用于小型阵列，但对大型阵列不起作用，所以我的问题是：我怎样才能优化这个功能？因为复杂性会增加，具体取决于合并的密钥。

使用PHP 7.0

Answer 1

您需要检查它们的长度是否相同，然后只需要一个简单的foreach：

foreach($a as $k => $v) {
    $result[$k] = array_merge($v, $b[$k]);
}

Answer 2

您可以改为使用array_replace_recursive()。

array_replace_recursive($a, $b);

演示：https://3v4l.org/bFIZ2

Answer 3

简单的解决方案可能是，

$c = [];

for($i=0; $i<count(array_keys($a)); $i++) {
  $c[$i] =array_merge($a[$i], $b[$i]);
}

print_r($c);

https://repl.it/KJNL

内核键上的PHP数组合并

3 个答案: