它是可能的,在PHP中,在不使用递归或引用的情况下扁平化(bi/multi)维数组?

我只对值感兴趣,所以键可以忽略,我认为在array_map()和array_values()的行。


当前回答

/**
 * For merging values of a multidimensional array into one 
 *
 * $array = [
 *     0 => [
 *         0 => 'a1',
 *         1 => 'b1',
 *         2 => 'c1',
 *         3 => 'd1'
 *     ],
 *     1 => [
 *         0 => 'a2',
 *         1 => 'b2',
 *         2 => 'c2',
 *     ]
 * ];
 *
 * becomes : 
 *
 * $array = [
 *     0 => 'a1',
 *     1 => 'b1',
 *     2 => 'c1',
 *     3 => 'd1',
 *     4 => 'a2',
 *     5 => 'b2',
 *     6 => 'c2',
 *     
 * ]
 */
array_reduce
(
    $multiArray
    , function ($lastItem, $currentItem) {
        $lastItem = $lastItem ?: array();
        return array_merge($lastItem, array_values($currentItem));
    }
);

依据片段

其他回答

对于php 5.2

function flatten(array $array) {
    $result = array();

    if (is_array($array)) {
        foreach ($array as $k => $v) {
            if (is_array($v)) {
                $result = array_merge($result, flatten($v));
            } else {
                $result[] = $v;
            }
        }
    }

    return $result;
}
/**
 * For merging values of a multidimensional array into one 
 *
 * $array = [
 *     0 => [
 *         0 => 'a1',
 *         1 => 'b1',
 *         2 => 'c1',
 *         3 => 'd1'
 *     ],
 *     1 => [
 *         0 => 'a2',
 *         1 => 'b2',
 *         2 => 'c2',
 *     ]
 * ];
 *
 * becomes : 
 *
 * $array = [
 *     0 => 'a1',
 *     1 => 'b1',
 *     2 => 'c1',
 *     3 => 'd1',
 *     4 => 'a2',
 *     5 => 'b2',
 *     6 => 'c2',
 *     
 * ]
 */
array_reduce
(
    $multiArray
    , function ($lastItem, $currentItem) {
        $lastItem = $lastItem ?: array();
        return array_merge($lastItem, array_values($currentItem));
    }
);

依据片段

仅平坦二维数组:

$arr = [1, 2, [3, 4]];
$arr = array_reduce($arr, function ($a, $b) {
     return array_merge($a, (array) $b);
}, []);

// Result: [1, 2, 3, 4]

这是我的解决方案,使用了一个参考:

function arrayFlatten($array_in, &$array_out){

    if(is_array($array_in)){
        foreach ($array_in as $element){
               arrayFlatten($element, $array_out);
        }
    }
    else{
        $array_out[] = $array_in; 
    }
}

$arr1 = array('1', '2', array(array(array('3'), '4', '5')), array(array('6')));

arrayFlatten($arr1, $arr2);

echo "<pre>";
print_r($arr2);
echo "</pre>";

您可以使用标准PHP库(SPL)来“隐藏”递归。

$a = array(1,2,array(3,4, array(5,6,7), 8), 9);
$it = new RecursiveIteratorIterator(new RecursiveArrayIterator($a));
foreach($it as $v) {
  echo $v, " ";
}

打印

1 2 3 4 5 6 7 8 9