replace all “foo” between ()

Question

I\'ve problem with my regex code, the problem is: I want to replace all \"foo\" values but only inside \"()\". Example:

try foo foo-foo (try foo inside , foo         


        

Answer 1

This finds all occurences of foo inside () and replace them with str_replace. From my experience I can say, that this is faster than preg_replace.

while (preg_match_all('/^(.*)(\([^\)]*foo[^\)]*\))(.*)$/', $string, $pat)) {
    $string = $pat[1] . str_replace('foo', 'boo', $pat[2]) . $pat[3];
}

Note the three groups: The string before the ( ($pat[1]), the string in the () which contains foo ($pat[2]) and the string behind the ) ($pat[3]).

Answer 2

If you can live with using a loop and replacing multiple times, this solution will work:

do {
  $string = preg_replace('/(\([^)]*)foo([^)]*\))/U', '\1boo\2', $string, -1, $count);
}while($count != 0);
echo $string;

Answer 3

Assuming parentheses are "valid", you can replace all foos that are followed by ), without a ( in between:

$str = preg_replace('/foo(?=[^()]*\))/', 'bar', $str);

Working example: http://ideone.com/xezU7

Another option, also assuming no nested pairs, is to match "(...)" tokens and use a callback, but it may be use of excessive force:

Callback method:

function replace_foo($matches) {
   return str_replace('foo', 'bar', $matches[0]);
}

use:

$str = preg_replace_callback("/\([^()]*\)/","replace_foo", $str);

Working example: http://ideone.com/ZzBem