Online PHP editor | refs for ECcqb

<?php function findMyThing($needle, $haystack) { // We need to set up a stack array + a while loop to avoid recursive functions for those are evil. // Recursive functions would also complicate things further in regard of returning. $stack = [ [ 'prefix' => [], 'value' => $haystack ] ]; // As long as there's still something there, don't stop while(count($stack) > 0) { // Copy the current stack and create a new, empty one $currentStack = $stack; $stack = []; // Work the stack for($i = 0; $i < count($currentStack); $i++) { // Iterate over the actual array foreach($currentStack[$i]['value'] as $key => $value) { // If the value is an array, then // 1. the key is a string (so we need to match against it) // 2. we might have to go deeper if(is_array($value)) { // We need to build the current prefix list regardless of what we're gonna do below $prefix = $currentStack[$i]['prefix']; $prefix[] = $key; // If the current key, is the one we're looking for, heureka! if($key == $needle) { return $prefix; } // Otherwise, push prefix & value onto the stack for the next loop to pick up else { $stack[] = [ 'prefix' => $prefix, 'value' => $value ]; } } // If the value is NOT an array, then // 1. the key is an integer, so we DO NOT want to match against it // 2. we need to match against the value itself elseif($value == $needle) { // This time append $value, not $key $prefix = $currentStack[$i]['prefix']; $prefix[] = $value; return $prefix; } } } } // At this point we searched the entire array and didn't find anything, so we return an empty array return []; } function getPath($haystack, $needle, $prefix=""){ $path = ""; foreach($haystack as $key=>$value){ if($path!="")break; if($key===$needle){ return $prefix.$key; break; } elseif($value===$needle) { return $prefix.$value; break; } elseif(is_array($value)) { $path.=getPath($value,$needle,$prefix.$key."=>"); } } return $path; } $arr = [ 'USA' => [ 'Alabama' => [ 'Montgomery', 'Birmingham' ], 'Arizona' => [ 'Phoenix', 'Mesa', 'Gilbert' ] ], 'Germany' => [ 'West Germany' => [ 'Bonn', 'Cologne' ] ] ]; print_r(getPath($arr, 'Alabama')); print_r(getPath($arr, 'Cologne'));