如何获取具有相同值的所有数组键

Question

我几乎尝试了所有方法，阅读了整个 php.net，但我似乎无法找到一种方法来获取具有相同值的所有键的数组。

例如这是数组：

Array
(
   [869] => 87
   [938] => 89
   [870] => 127
   [871] => 127
   [940] => 127
   [942] => 123
   [947] => 123
   [949] => 75
)

我们想要的数组是：

Array
(
    [1] => array
    (
        [1] => 870
        [2] => 871
        [3] => 940
    )
    [2] => array
    (
        [1] => 942
        [2] => 947
    )
)

Answer 1

这是一个可以做你想做的事情的函数。许多可能不是最简单的，但它确实有效：

<?php

$myArray = array(
   869 => 87,
   938 => 89,
   870 => 127,
   871 => 127,
   940 => 127,
   942 => 123,
   947 => 123,
   949 => 75
);
$newArray = $foundKeys = array();
$itt = 0;
foreach($myArray as $i => $x){
    foreach($myArray as $j => $y ){
        if($i != $j && !in_array($i,$foundKeys) && $x == $y){
           if(!is_array($newArray[$itt])){
               $newArray[$itt] = array($i);
           }
           array_push($newArray[$itt],$j);
           array_push($foundKeys,$j);
        }
    }
    $itt++;
}
print_r($newArray);

结果：

Array
(
    [2] => Array
        (
            [0] => 870
            [1] => 871
            [2] => 940
        )

    [5] => Array
        (
            [0] => 942
            [1] => 947
        )

)

Answer 2

如果你的第二个数组有你正在检查的值作为它的键，这会更容易做，例如

Array
(
    [127] => array
    (
        [1] => 870
        [2] => 871
        [3] => 940
    )
    [123] => array
    (
        [1] => 942
        [2] => 947
    )
)

然后你可以这样做：

<?php

$output = array();
foreach($your_array as $key => $current) {
    if( !array_key_exists($current, $output) ) {
        // create new entry
        $output[$current] = array( $key );
    } else {
        // add to existing entry
        $output[$current][] = $key;
    }
}

print_r($output);
?>

这应该返回上面的输出...

Answer 3

我的短代码。

$array =Array
(
   869 => 87,
   938 => 89,
   870 => 127,
   871 => 127,
   940 => 127,
   942 => 123,
   947 => 123,
   949 => 75
);

$return = array();
foreach ($array as $key => $value)
    $return[$value][] = $key;

var_dump(array_values($return));

http://3v4l.org/scDZ4