使用预定义的键转置PHP多维数组

$originalArray = array(
    'key1' => array('value1', 'value2'),
    'key2' => array('value3', 'value4'),
    'key3' => array('value5', 'value6')
);

$transposedArray = array();

foreach ($originalArray as $key => $values) {
    foreach ($values as $value) {
        if (!isset($transposedArray[$value])) {
            $transposedArray[$value] = array();
        }
        $transposedArray[$value][] = $key;
    }
}

print_r($transposedArray);

Array
(
    [value1] => Array
        (
            [0] => key1
        )

    [value2] => Array
        (
            [0] => key1
        )

    [value3] => Array
        (
            [0] => key2
        )

    [value4] => Array
        (
            [0] => key2
        )

    [value5] => Array
        (
            [0] => key3
        )

    [value6] => Array
        (
            [0] => key3
        )
)