在 PHP 中压缩多维数组？

Question

我确实有一个名为 $output 的数组。如果我执行以下操作...

<?php
print_r($output);
?>

...数组的内容看起来像这样...

Array ( [id] => 116 [the_key] => monday    [value] => 0 )
Array ( [id] => 116 [the_key] => tuesday   [value] => 1 )
Array ( [id] => 116 [the_key] => wednesday [value] => 0 )
Array ( [id] => 133 [the_key] => monday    [value] => 0 )
Array ( [id] => 133 [the_key] => tuesday   [value] => 1 )
Array ( [id] => 133 [the_key] => wednesday [value] => 0 )
Array ( [id] => 127 [the_key] => monday    [value] => 0 )
Array ( [id] => 127 [the_key] => tuesday   [value] => 0 )
Array ( [id] => 127 [the_key] => wednesday [value] => 0 )

...但我希望将内容做成这样的形式...

Array ( [id] => 116 [monday] => 0 [tuesday] => 1 [wednesday] => 0)
Array ( [id] => 133 [monday] => 0 [tuesday] => 1 [wednesday] => 0)
Array ( [id] => 127 [monday] => 0 [tuesday] => 0 [wednesday] => 0)

有什么方法可以在不循环一百万次的情况下做到这一点吗？

Answer 1

我不知道这是否属于“循环一百万次”，但为什么不尝试按id 对项目进行分组？

$newArray = array();

for($i = 0; $i < sizeof($output); $i++) {
    $curr = $output[$i];
    $id = $curr["id"];
    $day = $curr["the_key"];
    $value = $curr["value"];
    if(array_key_exists($id, $newArray)) {
        $newArray[$id][$day] = $value;
    } else {
        $newArray[$id] = array($day => $value);
    }
}

据我所知，$newArray 应该满足您的要求。