Re: Regex help

[swiftone]

I see a few potential problems here.

1. The regex you show won't work, because you didn't escape your / in </script>
2. the dot (.) doesn't match _anything_, by default it doesn't match newlines. The /s modifier at the end of the regex changes that behavior to what you want. (see perlre)

So  s/<script>(.*?)<\/script>//sg; should do what you want. I can't speak to the validity of what you're trying to do, but that should make the perl work :)

Update: Paren typo corrected per fglock below. (Was (.*)?, which would be a greedy match, with the ? essentially pointless, acting on a * modified group) I left the parens in to show a capture, but fglock is completely correct that you don't need the parens.

[fglock]

You mean  (.*?)

Actually you don't need parenthesis:

s/<script>.*?<\/script>//sg;

[Anonymous Monk]

Nope. The parenthesis are optional, but can be VERY useful. For example, say you want to remove the <script> and </script>, but be able to give some sort of warning about the script tags. For example, you may filter out:

<script>
malicious_code_to_do_something_nasty
</script>

If you use your regex as <script>(.*?)</script>, it saves the smallest amount (the ?) of anything (the .*) into a variable. That variable name depends on how many sets of parenthesis you've used. If it's the first (and only) time you use them, it gets saved into $1. If the second time, $2, and so forth. You can use it for something like this:

$text = "my name is john q user\n";
$text =~ s/^my name is (.*?) .*$/$1/;
# removes "my name is ", saves the next word, essentially, into $1, re
+moves the rest
print "hello, $text!\n";
# prints "hello, john!\n"

This is VERY useful in extracting information from strings.


-dingoStick.com