preg_replace of "Word" in a sentence and "Word." on the end of a sentence

Question

i want to preg_replace "Word" in PHP.

    $ret = 'I gave my Word to you.';    
    $pattern = '/\bWord\b/i';
    $ret = preg_replace($pattern,"Heart",$ret);
// echo $ret; = "I gave my Heart to you";

This works so far. But if the sentence is "I gave you my Word." or "I gave you my Word!" it doesn't change the "Word." into "Heart."

Solution

Not sure what the problem is. works for me.

<?
    $ret = 'I gave my Word to you Word.';
    $pattern = '/\bWord\b/i';
    $ret = preg_replace($pattern,"Heart",$ret);
    var_dump($ret);
?>

string(29) "I gave my Heart to you Heart."

Comments

[kennytm]

Works fine.

[Fanis Hatzidakis]

If it's such a simple replacement perhaps str_replace is faster than the regular expression.

[kennytm]

@Fanis: str_replace won't detect word boundaries.

[Fanis Hatzidakis]

@KennyTM you're absolutely right, I stand corrected.

[Oliver O'Neill]

To add to this, \b word boundaries matches words with [a-zA-Z0-9_] characters.

[kalimero]

Hmm, when i put this in a single php file it works, in my other code not. maybe the problem is in some other code. thanks so far for open my eyes