PHP preg_replace: Case insensitive match with case sensitive replacement

Question

I\'m using preg_replace in PHP to find and replace specific words in a string, like this:

$subject = \"Apple apple\";
print preg_replace(\'/\\bapple\\b/i\',          


        

Answer 1

You could do this with preg_replace_callback, but that's even more long winded:

$replacer = function($matches) {
    return ctype_lower($matches[0][0]) ? 'pear' : 'Pear';
};

print preg_replace_callback('/\bapple\b/i', $replacer, $subject);

This code just looks at the capitalization of the first character of the match to determine what to replace with; you could adapt the code to do something more involved instead.