Issue filtering words in contact form PHP based

Question

I having a issue filtering bad words inside a contact form message. It strips all the message except the first letter of the word. Any help?

below is just getting the info

<?php
$error = '';
if(!empty($_POST['username'])) $username = $_POST['username'];
if(!empty($_POST['email'])) $email = $_POST['email'];
if(!empty($_POST['subject'])) $subject = check($_POST['subject']);
if(!empty($_POST['message'])) $msg = filter($_POST['message']);

this is the function I am trying to use to strip the bad words and replace them

$bad_words = array(
'word1' => 'gosh',
'word2' => 'darn',);

 function filter($matches) {
 global $bad_words;
 $replace = $bad_words[$matches[0]];
 return !empty($replace) ? $replace : $matches[0];
 }

checks the drop down options and doesn't allow certain subjects to be emailed.

function check($str){
global $error;
if ($str == 'Mean Spirited Comment'){
  $error = 'You sent a Mean-Spirited Comment';
} else if ($str =='Political Comment'){
  $error = 'You sent a Political Comment';
}
 return $str;
}

places the info and sends

$to = 'email@email.com';
 if (!empty($subject) && !empty($msg) && !empty($email) && !empty($username)){
if ($error == ''){
  mail($to, $subject, $msg, 'From:' . $email);
} else {
  print $error;
}
}

?>

Answer 1

You could use str_replace since it can take array.

For instance:

$message = "Hello there my good friends! I am very happy to see you all today even though I feel like crap.";
$badWords = array("Crap", "Damnit", "Frack");
echo str_replace($badWords, "*", $message);

Results would be: Hello there my good friends! I am very happy to see you all today even though I feel like *.

Why re-invent new methods when PHP already offers plenty of useful ones? This should be enough to remove "bad words" from messages being sent.