Loop through the Alphabet in PHP to group letters into ranges A-C, C-E etc

Question

I want to create filters using the alphabet with 3-letter ranges like this: A-C,C-E,E-G etc

This is what I have so far:

function get_alphabet()
{
  $alphabet = '';
  for ($i=65; $i<=90; $i++) {  

    $letter = chr($i);
    $alphabet .= '<a title="filter results by letter '.$letter.'" 
href="/business/'.$letter.'"> ';
    $alphabet .= $letter;
    $alphabet .= '</a> | '; 
  }

  return $alphabet;
}
echo get_alphabet();

Answer 1

Try below code

function get_alphabet()
{
  $alphabet = '';
  for ($i=65; $i<=90; $i=$i+2) {  

    $letter = chr($i);
    $letter2 =($i+2>=90) ? chr(90) : chr($i+2);

    $links=$letter.'-'.$letter2;
    $alphabet .= '<a title="filter results by letter '.$links.'" 
href="/business/'.$links.'"> ';
    $alphabet .= $links;
    $alphabet .= '</a> | '; 

  }

  return $alphabet;
}
echo get_alphabet();

Output : A-C | C-E | E-G | G-I | I-K | K-M | M-O | O-Q | Q-S | S-U | U-W | W-Y | Y-Z |