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性能阵列连接?

arrays php

Anwar · 技术社区 · 7 年前

我想将相同的概念应用于 关联数组数组 而不是SQL。下面是用户及其地址的示例,下面是调用 array_join(array $array1, array $array2, string $key1, string $key2, string $new_key)

用户

Array
(
    [0] => Array
        (
            [id] => 1
            [name] => John
        )

    [1] => Array
        (
            [id] => 2
            [name] => Foo
        )

    [2] => Array
        (
            [id] => 3
            [name] => Baz
        )

)

地址:

Array
(
    [0] => Array
        (
            [id] => 1
            [user_id] => 1
            [street] => 53 Van Ness St
        )

    [1] => Array
        (
            [id] => 2
            [user_id] => 1
            [street] => 21 Overland St
        )

    [2] => Array
        (
            [id] => 3
            [user_id] => 1
            [street] => 101 Mountfort St
        )

    [3] => Array
        (
            [id] => 4
            [user_id] => 3
            [street] => 27 Sidney St
        )

)

(总之,用户1有3个地址,用户3有一个地址)

所需输出

Array
(
    [0] => Array
        (
            [id] => 1
            [name] => John
            [addresses] => Array
                (
                    [0] => Array
                        (
                            [id] => 1
                            [user_id] => 1
                            [street] => 53 Van Ness St
                        )

                    [1] => Array
                        (
                            [id] => 2
                            [user_id] => 1
                            [street] => 21 Overland St
                        )

                    [2] => Array
                        (
                            [id] => 3
                            [user_id] => 1
                            [street] => 101 Mountfort St
                        )

                )

        )

    [1] => Array
        (
            [id] => 2
            [name] => Foo
        )

    [2] => Array
        (
            [id] => 3
            [name] => Baz
            [addresses] => Array
                (
                    [0] => Array
                        (
                            [id] => 4
                            [user_id] => 3
                            [street] => 27 Sidney St
                        )

                )

        )

)

现在我想到的是:

<?php

function array_join(&$array1, $array2, $key1, $key2, $new_key) {
    foreach( $array1 as $index1 => $row1 ) {
        foreach( $array2 as $index2 => $row2 ) {
            if( $row2[$key2] === $row1[$key1] ) {
                $array1[$index1][$new_key][] = $row2;
            }
        }
    }
}

知道此函数平均需要1.2秒的时间,如何使其计算数据更快。,这对于6000行来说非常高。。。我怎样才能优化它呢?

1 回复 | 直到 7 年前

Barmar 7 年前

不要使用嵌套循环。创建使用 $key1 作为钥匙。然后你就可以循环通过 $array2 并找到匹配的元素 $array1 没有循环。

function array_join(&$array1, $array2, $key1, $key2, $new_key) {
    $assoc_array1 = array();
    // Create an associative array of references to the original array elements, keyed by $key1
    foreach ($array1 as &$row1) {
        $assoc_array1[$row1[$key1]] = $row1;
    }
    // Join the elements of the second array to those elements.
    foreach( $array2 as $row2 ) {
        $assoc_array1[$row2[$key2]][$new_key][] = $row2;
    }
}

这类似于数据库使用索引进行优化的方式 JOIN 操作。