Multidimensional Arrays Nested to Unlimited Depth

I have a multidimensional array nested to an unknown/unlimited depth. I'd like to be able to loop through every eleme开发者_如何学运维nt. I don't want to use, foreach(){foreach(){foreach(){}}} as I don't know the depth.

I'm eventually looking for all nested arrays called "xyz". Has anyone got any suggestions?

I'm eventually looking for all nested arrays called "xyz". Has anyone got any suggestions?

Sure. Building on the suggestions to use some iterators, you can do:

$iterator = new RecursiveIteratorIterator(
    new RecursiveArrayIterator($array),
    RecursiveIteratorIterator::SELF_FIRST
);
foreach ($iterator as $key => $item) {
    if (is_array($item) && $key === 'xyz') {
        echo "Found xyz: ";
        var_dump($item);
    }
}

The important difference between the other answers and this being that the RecursiveIteratorIterator::SELF_FIRST flag is being employed to make the non-leaf (i.e. parent) items (i.e. arrays) visible when iterating.

You could also make use of a ParentIterator around the array iterator, rather than checking for arrays within the loop, to make the latter a little tidier.

Recursion.

Write a function that walks one array; for each element that is also an array, it calls itself; otherwise, when it finds the target string, it returns.

There is a vast difference between unknown and unlimited. However, you can make use of the SPL Iterators instead of using multiple nested foreach loops.

Example:

$array_obj = new RecursiveIteratorIterator(new RecursiveArrayIterator($array));
foreach($array_obj as $key => $value) {
   echo $value;
}

Take a look to the RecursiveIteratorIterator interface.

$interface = new RecursiveIteratorIterator( new RecursiveArrayIterator($your_array) );
foreach($interface as $k=>$v) { /* your function*/  }

Using the comments above, I've found the answer:

function findXyz($array){
    foreach($array as $foo=>$bar){
      if (is_array($bar)){
         if ($bar["xyz"]){
             echo "<br />The array of xyz has now been found";
             print_r($bar['xyz']);
         }else{
            findXyz($bar);   
         } 
      }
    } 
}
findXyz($myarray);

This loops through all nested arrays and looks for any element who has a sub-array of xyz, as per my original request. array_walk_array and RecursiveIteratorIterator were unable to achieve this.

Have you thought about using array_walk_recursive for this?

Another (slower) approach would be to flatten the array first before performing a search, ie:

$myarray = array('a','b',array(array(array('x'),'y','z')),array(array('p')));

function array_flatten($array,$return)
{
    for($x = 0; $x <= count($array); $x++)
    {
        if(is_array($array[$x]))
        {
            $return = array_flatten($array[$x],$return);
        }
        else
        {
            if($array[$x])
            {
                $return[] = $array[$x];
            }
        }
    }
    return $return;
}

$res = array_flatten($myarray,array());

Or, for a recursive search, see here for an example:

function arrayRecursiveSearch($needle, $haystack, $path=""){
  if(!is_array($haystack)){
    die("second argument is not array");
  }

  global $matches;

  foreach($haystack as $key=>$value)
  {
    if(preg_match("/$needle/i", $key)){
      $matches[] = array($path . "$key/", "KEY: $key");
    }

    if(is_array($value)){
      $path .= "$key/";
      arrayRecursiveSearch($needle, $value, $path);
      unset($path);
    }else{
      if(preg_match("/$needle/i", $value)){
        $matches[] = array($path . "$key/", "VALUE: $value");
      }
    }
  }

  return $matches;
}

$arr = array("Asia"=>array('rambutan','duku'),
              "Australia"=>array('pear','kiwi'),
              "Arab"=>array('kurma'));

print_r(arrayRecursiveSearch("ra",$arr));