# Help with a regex **URL:** \ **Category:** Rails\ **Created:** [December 7, 2006, 4:07pm UTC](https://www.ruby-forum.com/t/help-with-a-regex/78647 "2006-12-07T16:07:14Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![ryan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/a8b319/32.png) [@ryan](https://www.ruby-forum.com/u/ryan)\ **Post date:** [December 7, 2006, 4:07pm UTC](https://www.ruby-forum.com/t/help-with-a-regex/78647/1 "2006-12-07T16:07:14Z")
I’m trying to find a block of text within ``` text ``` tags, and replace it with nothing. However, I’m not experienced with regular expressions. Here’s what I want to do. s = “Here are some words. ``` this is a code snippet ``` More words.” s.gsub([regex\_goes\_here],’’) Now, s becomes: $: s =\> “Here are some words. More words.” I just don’t know the regular expression for this. Is it something like… s.gsub(/^[: ``` :][: ``` :]$, ‘’) ??? That doesn’t seem to work. Any help on this? Thanks in advance. ---
**Author:** ![ryan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/a8b319/32.png) [@ryan](https://www.ruby-forum.com/u/ryan)\ **Post date:** [December 7, 2006, 4:21pm UTC](https://www.ruby-forum.com/t/help-with-a-regex/78647/2 "2006-12-07T16:21:13Z")
gsub(/ ``` .*/, “ ``` ``` ”) ``` ---
**Author:** ![ryan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/a8b319/32.png) [@ryan](https://www.ruby-forum.com/u/ryan)\ **Post date:** [December 7, 2006, 4:41pm UTC](https://www.ruby-forum.com/t/help-with-a-regex/78647/3 "2006-12-07T16:41:21Z")
Shouldn’t the second argument be single quote followed by another single quote to remove the text between the tags as well as the tags? ---
**Author:** ![ryan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/a8b319/32.png) [@ryan](https://www.ruby-forum.com/u/ryan)\ **Post date:** [December 7, 2006, 5:05pm UTC](https://www.ruby-forum.com/t/help-with-a-regex/78647/4 "2006-12-07T17:05:09Z")
Bala P. wrote: > Shouldn’t the second argument be single quote followed by another single > quote to remove the text between the tags as well as the tags? That’s exactly what I was thinking. I have padding in the CSS on my “pre” tags, so if there isn’t any text there, I don’t want a block element showing. But that wasn’t the part I asked about - and it’s easy enough to just switch it out and see if that works. The hard part was the regex part, which I really appreciate. Regular expressions are always so easy once I see it, but can be complicated when I’m trying to write one. Thanks again for the help… ---
**Author:** ![ryan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/a8b319/32.png) [@ryan](https://www.ruby-forum.com/u/ryan)\ **Post date:** [December 7, 2006, 5:45pm UTC](https://www.ruby-forum.com/t/help-with-a-regex/78647/5 "2006-12-07T17:45:49Z")
Ryan, here is the Ruby mailing list: ruby-talk-google removed\_email\_address@domain.invalid [http://groups.google.com/group/ruby-talk-google](http://groups.google.com/group/ruby-talk-google) For Ruby related questions, you will find this group very helpful. ---
**Author:** ![ryan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/a8b319/32.png) [@ryan](https://www.ruby-forum.com/u/ryan)\ **Post date:** [December 7, 2006, 7:24pm UTC](https://www.ruby-forum.com/t/help-with-a-regex/78647/6 "2006-12-07T19:24:35Z")
So, maybe I’m doing something wrong, but this isn’t working: gsub(/ ``` .*/, “ ``` ``` ”) Here’s what I have: #application\_helper.rb def strip\_pre\_block(text) text.gsub(/ ``` .*/, ‘’) text end #view \<%= strip\_pre\_block(to\_html(p.body)) %\> The to\_html converts the textile text into html. See anything wrong with this regex? ``` ``` ---
**Author:** ![ryan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/a8b319/32.png) [@ryan](https://www.ruby-forum.com/u/ryan)\ **Post date:** [December 7, 2006, 8:14pm UTC](https://www.ruby-forum.com/t/help-with-a-regex/78647/7 "2006-12-07T20:14:30Z")
yes. You’re gsubbing the text, but not doing anything with it. Then you’re returning your original text. Take that last statement out of your method, then it will return the results of the gsub. ---
**Author:** ![ryan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/a8b319/32.png) [@ryan](https://www.ruby-forum.com/u/ryan)\ **Post date:** [December 7, 2006, 9:06pm UTC](https://www.ruby-forum.com/t/help-with-a-regex/78647/8 "2006-12-07T21:06:50Z")
I don’t think anyone mentioned that the regex will not work if you have more than one ``` block in the text. In other words, it will fail in this case: str = “ ``` DeleteMe ``` SaveMe ``` DeleteMe ``` ” Because the .\* is greedy, it’ll get rid of the entire string, including the SaveMe part. If you KNOW there won’t be any HTML tags inbetween the ``` ``` tags, you can do the following: def strip\_pre\_block(text) text.gsub(/ ``` [^<]*/,’’) end HTML is difficult to parse correctly using Regular Expressions. Ordinarily I would recommend using a real HTML parser, but in your case, you may be able to use the amended regex above, or even process the textile before you convert it to HTML. ``` ``` ---
**Author:** ![ryan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/a8b319/32.png) [@ryan](https://www.ruby-forum.com/u/ryan)\ **Post date:** [December 7, 2006, 9:19pm UTC](https://www.ruby-forum.com/t/help-with-a-regex/78647/9 "2006-12-07T21:19:29Z")
Thank you - the regex you gave me worked like a charm.