'Simplify a nested array into a single level array [duplicate]

Possible Duplicate:
How to Flatten a Multidimensional Array?

Let's say I have an array like this:

array (
  1 => 
  array (
    2 => 
    array (
      16 => 
      array (
        18 => 
        array (
        ),
      ),
      17 => 
      array (
      ),
    ),
  ),
  14 => 
  array (
    15 => 
    array (
    ),
  ),
)

How would I go about tranforming it into array like this?

array(1,2,16,18,17,14,15);
php


Solution 1:[1]

how about some recursion

$result = array();
function walkthrough($arr){ 
    $keys = array_keys($arr);
    array_push($result, $keys);
    foreach ($keys as $key)
    {
        if (is_array($arr[$key]))
           walkthrough($arr[$key]);
        else
           array_push($result,$arr[$key]);
    }
    return $result;
}
walkthrouth($your_arr);

P.S.:Code can be bugged, but you've got an idea :)

Solution 2:[2]

function flattenArray($array) {
 $arrayValues = array();
 foreach (new RecursiveIteratorIterator( new RecursiveArrayIterator($array)) as $val) {
  $arrayValues[] = $val;
 }
 return $arrayValues;
} // function flattenArrayIndexed()

Solution 3:[3]

If we consider the nested array as a tree structure, you can apply depth first traversal to convert it into a list. That is, into a single array you desire.

Solution 4:[4]

I have searched all similar questions and it seems there is no way without a recursion that would keep the keys order intact.

So I just went with classic recursion:

function getArrayKeysRecursive(array $theArray)
{
    $aArrayKeys = array();
    foreach ($theArray as $k=>$v) {
        if (is_array($v)) {
            $aArrayKeys = array_merge($aArrayKeys, array($k), getArrayKeysRecursive($v));
        } else {
            $aArrayKeys = array_merge($aArrayKeys, array($k));
        }
    }
    return $aArrayKeys;
}

Sources

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Source: Stack Overflow

Solution Source
Solution 1 xxx
Solution 2 Mark Baker
Solution 3 Shamim Hafiz - MSFT
Solution 4 Richard Knop

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