PHP preg_replace word but not if there is certain characters preceding the word

Question

I want to replace a word with PHP preg_replace. It should not replace the word if the characters /> exist before this word.

i.e.

this should be replaced if matched

$word = "foo";

this should not be replaced if matched

$word = "/>foo";

[Don't use regexes to manipulate html.](http://stackoverflow.com/questions/1732348/regex-match-open-tags-except-xhtml-self-contained-tags/1732454#1732454) — Marc B, Oct 12 '11 at 14:42
Don't want to manipulate html. In my case it will alwaysbe />foo — williamcarswell, Oct 12 '11 at 14:49

score 8 · Accepted Answer · answered Oct 12 '11 at 14:46

8

Here you are ;-)

(?<!/>)foo

good luck

answered Oct 12 '11 at 14:46

Fischermaen

I tried your regex but seems to replace the test string "/>foo". – Aurelio De Rosa Oct 12 '11 at 14:50
1

@AurelioDeRosa: How did you try it? This is *the* correct answer. It might be helpful to add that in PHP, you need delimiters around the regex, so it'll look something like `$result = preg_replace('%(?<!/>)foo%', 'REPLACED', $subject);` – Tim Pietzcker Oct 12 '11 at 15:45
Did anyone try it in with PHP yet? – williamcarswell Oct 12 '11 at 16:14
This is the correct answer, i got it working with @TimPietzcker suggestion – williamcarswell Oct 12 '11 at 16:23
@AurelioDeRosa: Sorry for the mix up, I'm a "regex-junkie" but not a PHP-pro :-D – Fischermaen Oct 12 '11 at 21:10

score 0 · Answer 2 · answered Oct 12 '11 at 15:37

0

if ($word[0] != '/' && $word[1] != '>') {
    $new_string = str_replace($word, $replace, $string);
}

answered Oct 12 '11 at 15:37

2 Answers2