gistfile1.php

<?php
$string = "1234567890";
$n = 3;

$numberOfCarachter = strlen($string);
echo "Number of Character: ".$numberOfCarachter."\n";
$newString = array();
$stringInitialPosition = 0;


while($stringInitialPosition < $numberOfCarachter){
  echo "Initial Position: ".$stringInitialPosition."\n";
  echo "Final Position: ".$stringFinalPosition."\n";
  echo "---------------------------------\n";
  
  $subString = substr($string, $stringInitialPosition, $n);
  echo "Substring: ".$subString."\n";
  $newString[] = $subString;
  $stringInitialPosition += $n;
}
var_dump($newString);
$string = implode(' ', $newString);

echo $string."\n"; 

?>