Wsrtjtyk

I would like to make a list of every possible combination of inserted numbers. I figured out this way:

     for($x=1;$x<=3;$x++){

         for($y=1;$y<=3;$y++){

             for($e=1;$e<=3;$e++){



             echo $x.$y.$e."</br>" ;



            }

          }   

        }

But the problem with these nested loops is that I have to put manually as many loops as I have digits in a number. Is there a way to make it automatically/programmatically?

You can use a recursive function to loop again when necessary.

For example, this function prints out the numbers 1-3 for a given number of digits (minimum allowed value is 1, any lower it will still output all single-digit numbers in that range):

function variations($digits, $prefix = '') {

    for ($i = 1; $i <= 3; $i++) {

        $variation = $prefix . $i;



        if ($digits > 1) {

            variations($digits - 1, $variation);

        } else {

            echo $variation . "<br />";

        }

    }

}



variations(1);

/*

1<br />2<br />3<br />

*/



variations(2);

/*

11<br />12<br />13<br />21<br />22<br />23<br />31<br />32<br />33<br />

*/

https://3v4l.org/Rj2u7 (outputs a linebreak instead of "<br />" for display purposes)

Here's a slight variation that returns the generated numbers in an array instead of echo'ing them directly, so you can use them for some other purpose if you'd like:

function variations($digits, $prefix = '') {

    $result = ;



    for ($i = 1; $i <= 3; $i++) {

        $variation = $prefix . $i;



        if ($digits > 1) {

            $result = array_merge($result, variations($digits - 1, $variation));

        } else {

            $result = $variation;

        }

    }



    return $result;

}



print_r(variations(1));

/*

Array

(

    [0] => 1

    [1] => 2

    [2] => 3

)

*/



print_r(variations(2));

/*

Array

(

    [0] => 11

    [1] => 12

    [2] => 13

    [3] => 21

    [4] => 22

    [5] => 23

    [6] => 31

    [7] => 32

    [8] => 33

)

*/

https://3v4l.org/LBrjA