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

非递归,非基于引用的实现,这可能比基于递归的实现更容易理解。 可以管理任意深度多维数组,不能平化关联数组。 它的工作原理是每个周期将数组压平一层,直到它完全有效。

function array_flatten(): array{
    $result = func_get_args();
    // check all elements of $list are not arrays
    $_is_flat = function (array $list): bool {
        foreach ($list as $val) {
            if (is_array($val)) {
                return false;
            }
        }
        return true;
    };
    do {
        $tmp = [];
        foreach ($result as $val) {
            if (is_array($val)) {
                if (!array_is_list($val)) {
                    throw new \Exception(sprintf("array_flatten can't handle associative arrays: %s", json_encode($val)));
                }
                $tmp = array_merge($tmp, $val);
            } else {
                $tmp[] = $val;
            }
        }
        $result = $tmp;
    } while (!$_is_flat($result));
    return $result;
}

以下是它处理的情况:

assertEquals(array_flatten(1, 2), $expected = [1, 2], 'array_flatten 1a');
assertEquals(array_flatten([1], [2]), $expected = [1, 2], 'array_flatten 1b');
assertEquals(array_flatten([1], [[2], 3]), $expected = [1, 2, 3], 'array_flatten 1c');
assertEquals(array_flatten(1, [2, 3], [4, 5]), $expected = [1, 2, 3, 4, 5], 'array_flatten 2');
assertEquals(array_flatten(2, 3, [4, 5], [6, 7], 8), $expected = [2, 3, 4, 5, 6, 7, 8], 'array_flatten 3');
assertEquals(array_flatten([2, 3, [4, 5], [6, 7], 8]), $expected = [2, 3, 4, 5, 6, 7, 8], 'array_flatten 4');
assertEquals(array_flatten([2, [3, [4, [5]], [6, [7]], 8]]), $expected = [2, 3, 4, 5, 6, 7, 8], 'array_flatten complex');

其他回答

二维数组的解

请试试这个:

$array  = your array

$result = call_user_func_array('array_merge', $array);

echo "<pre>";
print_r($result);

编辑:8月21日-13日

下面是适用于多维数组的解决方案:

function array_flatten($array) {
    $return = array();
    foreach ($array as $key => $value) {
        if (is_array($value)){
            $return = array_merge($return, array_flatten($value));
        } else {
            $return[$key] = $value;
        }
    }

    return $return;
}

$array  = Your array

$result = array_flatten($array);

echo "<pre>";
print_r($result);

裁判:http://php.net/manual/en/function.call-user-func-array.php

因为这里的代码看起来很可怕。下面是一个将多维数组转换为html格式兼容语法的函数,但它更容易阅读。

/**
 * Flattens a multi demensional array into a one dimensional
 * to be compatible with hidden html fields.
 *
 * @param array $array
 *  Array in the form:
 *  array(
 *    'a' => array(
 *      'b' => '1'
 *    )
 *  )
 *
 * @return array
 *  Array in the form:
 *  array(
 *    'a[b]' => 1,
 *  )
 */
function flatten_array($array) {
  // Continue until $array is a one-dimensional array.
  $continue = TRUE;
  while ($continue) {
    $continue = FALSE;

    // Walk through top and second level of $array and move 
    // all values in the second level up one level.
    foreach ($array as $key => $value) {
      if (is_array($value)) {
        // Second level found, therefore continue.
        $continue = TRUE;

        // Move each value a level up.
        foreach ($value as $child_key => $child_value) {
          $array[$key . '[' . $child_key . ']'] = $child_value;
        }

        // Remove second level array from top level.
        unset($array[$key]);
      }
    }
  }

  return $array;
}
<?php
//recursive solution

//test array
$nested_array = [[1,2,[3]],4,[5],[[[6,[7=>[7,8,9,10]]]]]];

/*-----------------------------------------
function call and return result to an array
------------------------------------------*/
$index_count = 1;
$flatered_array = array();
$flatered_array = flat_array($nested_array, $index_count);

/*-----------------------------------------
Print Result
-----------------------------------------*/
echo "<pre>";
print_r($flatered_array);


/*-----------------------------------------
function to flaten an array 
-----------------------------------------*/
function flat_array($nested_array, & $index_count, & $flatered_array) {

  foreach($nested_array AS $key=>$val) {
      if(is_array($val)) {
        flat_array($val, $index_count, $flatered_array);
      }
      else {
        $flatered_array[$index_count] = $val;
        ++$index_count;
      }      
  }

return $flatered_array;
}
?>

诀窍是通过引用传递源数组和目标数组。

function flatten_array(&$arr, &$dst) {
    if(!isset($dst) || !is_array($dst)) {
        $dst = array();
    }
    if(!is_array($arr)) {
        $dst[] = $arr;
    } else {
        foreach($arr as &$subject) {
            flatten_array($subject, $dst);
        }
    }
}

$recursive = array('1', array('2','3',array('4',array('5','6')),'7',array(array(array('8'),'9'),'10')));
echo "Recursive: \r\n";
print_r($recursive);
$flat = null;
flatten_array($recursive, $flat);

echo "Flat: \r\n";
print_r($flat);

// If you change line 3 to $dst[] = &$arr; , you won't waste memory,
// since all you're doing is copying references, and imploding the array 
// into a string will be both memory efficient and fast:)

echo "String:\r\n";
echo implode(',',$flat);

任何想要解决这个问题的人;这里有一个选择:

获取具有不同键值配置的数组的数组:

$test_array = array(
    array('test' => 0, 0, 0, 0),
    array(0, 0, 'merp' => array('herp' => 'derp'), 0),
    array(0, 0, 0, 0),
    array(0, 0, 0, 0)
);
$it = new RecursiveIteratorIterator(new RecursiveArrayIterator($test_array));
var_dump( iterator_to_array($it, false) ) ; 

这将只从每个数组中获取值,并返回单个平面数组。

result值的输出:

0 0 0 0 0 0 derp 0 0 0 0 0 0 0 0 0