Multidimensional Arrays Nested to Unlimited Depth - php

Question

I have a multidimensional array nested to an unknown/unlimited depth.
I'd like to be able to loop through every element.
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?

Answer 1

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.

Answer 2

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.

Answer 3

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;
}

Answer 4

Take a look to the RecursiveIteratorIterator interface.
$interface = new RecursiveIteratorIterator( new RecursiveArrayIterator($your_array) );
foreach($interface as $k=>$v) { /* your function*/ }

Answer 5

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.

Answer 6

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));