remove_or_add.php

<?php
// 7 kyu - Exclamation marks series #9: Remove or add a exclamation mark at the end of words of the sentence
// Remove or add a exclamation mark at the end of words of the sentence. Words are separated by spaces in the sentence. That is: If a word has one ! at the end, remove it; If a word has no ! at the end, add a ! to the end; If there are more than one ! at the end of word, keep it.
//
// Examples
// removeOrAdd("Hi!") === "Hi"
// removeOrAdd("Hi! Hi!") === "Hi Hi"
// removeOrAdd("Hi! Hi") === "Hi Hi!"
// removeOrAdd("Hi! Hi Hi!!") === "Hi Hi! Hi!!"
// removeOrAdd("!Hi! !Hi !Hi!!") === "!Hi !Hi! !Hi!!"

function remove_or_add(string $s): string {
  return implode(' ', array_map(function ($w) {
    if ($w[strlen($w) - 1]  !== '!') {
      return $w . '!';
    } else if ( $w[strlen($w) - 1] === '!' && $w[strlen($w) - 2] !== '!') {
      return substr($w, 0, -1);
    } else {
      return $w;
    }
  },explode(' ', $s)));
}

// Alternative Solution:
// function remove_or_add(string $s): string {
//   return implode(' ', array_map(function ($w) {
//     if (preg_match('/[^\!]$/', $w)) return $w . '!';
//     if (preg_match('/\!{2,}$/', $w)) return $w;
//     return preg_replace('/\!$/', '', $w);
//   },explode(' ', $s)));
// }

?>