Nested Loops in PHP

Loops, which you already know how to work with, can be nested inside each other. For example, let's solve the following problem: display the string:

You can't manage with one loop here - you need to run two loops nested inside each other: the first loop will iterate over numbers (first 1, then 2, then 3 and so on up to 9), and the second loop will repeat these numbers three times.

Let's implement it:

php<?php
  for ($i = 1; $i <= 9; $i++) {
    for ($j = 1; $j <= 3; $j++) {
      echo $i;
    }
  }
?>

Pay attention: the first loop has a counter $i, the second one $j, and if there is a third loop - its counter will be the variable $k. These are standard generally accepted names, you should use them.