PHP recursive multidimensional loop

Question

$printArr = recursive($newArray); //calls recursive function
$data = [];
var_dump($data);
var_dump($printArr);
 function recursive($array, $level = 0)
 {
 $searchingValue = 'tableName';
 foreach($array as $key => $value)
 {
 //If $value is an array.
 if(is_array($value))
 {
 recursive($value, $level + 1);
 } 
 else
 {
 //It is not an array, so print it out.
 if($key == $searchingValue)
 {
 echo "[".$key . "] => " . $value, '<br>';
 $data[] = $value;
 }
 }
 }
 }

So I have this function and I am trying to save $value value into $data[] array. But it always returns it empty and I don't know why I can't get $value saved outside the function. If i echo $value I get what i need but like I've mentioned the variables doesn't get saved in this case - table names.

• Lovepreet Singh: Have you called recursive() function anywhere? Or just declared and printed $data array which is already blank.
• MonkeyZeus: What purpose does $level serve?
• MonkeyZeus: Can you explain the goal of the function which you have written?
• MonkeyZeus: Or even show some sample input and both actual vs. expected output
• Tinabot: Yes I did. $printArr = recursive($newArray); //calls recursive function $data = []; var_dump($data); var_dump($printArr); I've also added in the question code.

Answer 1

You need to pass the $data to your recursive function. Also you need to return the $data.

Try this code :

function recursive($array, $level = 0, $data =[])
{
 $searchingValue = 'tableName';
 foreach($array as $key => $value)
 {
 //If $value is an array.
 if(is_array($value))
 {
 recursive($value, $level + 1 , $data);
 } 
 else
 {
 //It is not an array, so print it out.
 if($key == $searchingValue)
 {
 echo "[".$key . "] => " . $value, '<br>';
 $data[] = $value;
 }
 }
 }
 return $data;
}

• Eakethet: If you pass by reference, you dont need to return data, choose one. Also, you are not passing data by reference in example.
• Tinabot: It worked! I can't believe I didn't think to pass reference. Thank you so much!

Answer 2

You can't access variable $data, which is outside the function, from the function. You need to pass it by reference or return it. Small example

<?php
$a = 1;
// Your case
function b() {
 $a = 4;
 return true;
}
// Passing by reference
function c(&$d) {
 $d = 5;
 return true;
}
// Using return
function d($d) {
 $d = 6;
 return $d;
}
b();
var_dump($a);
c($a);
var_dump($a);
$a = d($a);
var_dump($a);

https://3v4l.org/UXFdR