Question

I have this difficult task (for me at least).
This is abstract question, mathematical i’d say.
Let’s assume I have 2 inputs:

1. a keyword (string)
2. a number (deepness level)

and submit button.

This keyword returns me 8 other keywords from a database that are similar to this string.
And for each of that 8 keywords I need to call same function that will return me another 8 similar keywords of all these 8 strings I have already returned.
Here comes the “level” number. I need to go deeper inside every of returned string depending on level number I entered.

For example: If the level number is 2, then we will call the function 9 times. First time for the original keyword, and 8 times for each returned keyword.
If the level number is 3, then the function will be called 73 times. Like in the previous example, but plus for another 8 keywords we have returned. I think there will be a couple of loops inside loops, but can’t figure it out by myself. Will appreciate your suggestions.

Here’s the main code that I have wrote which is probably unsufficient:

$keywords = preg_split('/$\R?^/m', trim($_POST['keyword']));
$keywords = array_map('trim', $keywords);
$level = $_POST['level'];
if (!$level || $level < 2) {
    echo '<b>Level was either 1 or null</b>';
}
foreach ($keywords as $keyword) {
    $results = getResults($keyword);
    if ($level && $results) {
        for ($i = 0; $i < sizeof($results); $i++) {
            $results1 = getResults($results[$i]);
            for ($j = 0; $j < $level; $j++) {
                $results1 = getResults($results1[$i])
            }
        }
    }
}

The output should be something like this:

1->
   2
   ->
      3
      3
      3
      3
      3
      3
      3
      3
   2->
   2->
   2->
   2->

Answer 1

You need to understand what recursion means and how you can use it in your code. Basically you need to call the same function inside itself, n times where n is the deepness level of your request.

Start with some little examples like Fibonacci series, and you will find the way to implement your function.

All is based on a condition ($deepness > 0).

Here’s a little suggestion (in pseudocode) based on what I understood.

function findSimilar($words,$deepness) {
    if($deepness == 0) {
        return similarWordsOf($words);
    } else {
        return similarWordsOf(findSimilar($words,$deepness -1));
    }
}