你可以用茴香酒来做:

 $result = Arrays::flatten($multidimensional);

看到:

我需要用HTML输入格式表示PHP多维数组。

$test = [
    'a' => [
        'b' => [
            'c' => ['a', 'b']
        ]
    ],
    'b' => 'c',
    'c' => [
        'd' => 'e'
    ]
];

$flatten = function ($input, $parent = []) use (&$flatten) {
    $return = [];

    foreach ($input as $k => $v) {
        if (is_array($v)) {
            $return = array_merge($return, $flatten($v, array_merge($parent, [$k])));
        } else {
            if ($parent) {
                $key = implode('][', $parent) . '][' . $k . ']';

                if (substr_count($key, ']') != substr_count($key, '[')) {
                    $key = preg_replace('/\]/', '', $key, 1);
                }
            } else {
                $key = $k;
            }           

            $return[$key] = $v;
        }
    }

    return $return;
};

die(var_dump( $flatten($test) ));

array(4) {
  ["a[b][c][0]"]=>
  string(1) "a"
  ["a[b][c][1]"]=>
  string(1) "b"
  ["b"]=>
  string(1) "c"
  ["c[d]"]=>
  string(1) "e"
}

使用递归。希望在看到它有多简单的时候，你对递归的恐惧会在你看到它有多简单的时候消失。

function flatten($array) {
    if (!is_array($array)) {
        // nothing to do if it's not an array
        return array($array);
    }

    $result = array();
    foreach ($array as $value) {
        // explode the sub-array, and add the parts
        $result = array_merge($result, flatten($value));
    }

    return $result;
}


$arr = array('foo', array('nobody', 'expects', array('another', 'level'), 'the', 'Spanish', 'Inquisition'), 'bar');
echo '<ul>';
foreach (flatten($arr) as $value) {
    echo '<li>', $value, '</li>';
}
echo '<ul>';

输出:

<ul><li>foo</li><li>nobody</li><li>expects</li><li>another</li><li>level</li><li>the</li><li>Spanish</li><li>Inquisition</li><li>bar</li><ul>

这个解是非递归的。注意，元素的顺序会有些混合。

function flatten($array) {
    $return = array();
    while(count($array)) {
        $value = array_shift($array);
        if(is_array($value))
            foreach($value as $sub)
                $array[] = $sub;
        else
            $return[] = $value;
    }
    return $return;
}

<?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;
}
?>

如果你想保留中间键:

function flattenArray(array &$result, $value, string $key = "")
{
    if (!is_array($value)) {
        $result[$key] = $value;
        return $result;
    }
    foreach ($value as $subKey => $subArray) {
        $newKey = $key !== "" ? $key . "_" . $subKey : $subKey;
        flattenArray($result, $subArray, $newKey);
    }
    return $result;
}

$nestedArray = [
    "name" => "John",
    "pets" => [
        ["id" => 1, "name" => "snooop"],
        ["id" => 2, "name" => "medor"],
    ],
    "job" => ["title" => "developper"],
];

$intermediateResult = [];
$flattened = flattenArray($intermediateResult, $nestedArray);
var_dump($flattened);

这将输出:

array(6) {
["name"]=>
  string(4) "John"
        ["pets_0_id"]=>
  int(1)
  ["pets_0_name"]=>
  string(6) "snooop"
        ["pets_1_id"]=>
  int(2)
  ["pets_1_name"]=>
  string(5) "medor"
        ["job_title"]=>
  string(10) "developper"
}

看到https://ideone.com/KXLtzZ stdout