# Regular Expressions **URL:** \ **Category:** Rails\ **Created:** [November 29, 2005, 10:42pm UTC](https://www.ruby-forum.com/t/regular-expressions/49101 "2005-11-29T22:42:13Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![mememe](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/977dab/32.png) [@mememe](https://www.ruby-forum.com/u/mememe)\ **Post date:** [November 29, 2005, 10:42pm UTC](https://www.ruby-forum.com/t/regular-expressions/49101/1 "2005-11-29T22:42:13Z")
Does anyone know how can I replace all [http://example.com](http://example.com) to [http://example.com](http://example.com) in text? ---
**Author:** ![mememe](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/977dab/32.png) [@mememe](https://www.ruby-forum.com/u/mememe)\ **Post date:** [November 29, 2005, 11:42pm UTC](https://www.ruby-forum.com/t/regular-expressions/49101/2 "2005-11-29T23:42:52Z")
Dmytro, I’m not a Ruby guru yet, so sorry that it’s in perl (maybe a Ruby master can deliver the syntax). First make sure the initial url has it’s special characters escaped $escaped\_url = regex.escape($url); search and replace the url with the full link. The $1 is a so called backreference to whats between the brackets “(” and “)”. ``` $html_anchor =~ s/($escaped_url)/$1<\/a>/g ``` (As you can see the “” is placed as “\” the slash is a special character and therefore escaped with the "" I’ve tried it and it works. There’s only one ‘but’. The url fed into the regex is not checked on valid syntax yet. Hope this helps. Regards, Gerard. On Tuesday 29 November 2005 22:33, Dmytro tried to type something like: > Does anyone know how can I replace all [http://example.com](http://example.com) to [http://example.com](http://example.com) in text? > > * * * > > Rails mailing list > removed\_email\_address@domain.invalid > [http://lists.rubyonrails.org/mailman/listinfo/rails](http://lists.rubyonrails.org/mailman/listinfo/rails) – “Who cares if it doesn’t do anything? It was made with our new Triple-Iso-Bifurcated-Krypton-Gate-MOS process …” My $Grtz =~ Gerard; ~ :wq! ---
**Author:** ![mememe](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/977dab/32.png) [@mememe](https://www.ruby-forum.com/u/mememe)\ **Post date:** [November 29, 2005, 11:50pm UTC](https://www.ruby-forum.com/t/regular-expressions/49101/3 "2005-11-29T23:50:58Z")
Assuming your text is in a string called ‘text’, you just need to perform some regexp-fu! result = text.gsub(/http://\S+/, ‘\0’) Cheers! -DF ---
**Author:** ![mememe](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/977dab/32.png) [@mememe](https://www.ruby-forum.com/u/mememe)\ **Post date:** [November 29, 2005, 11:46pm UTC](https://www.ruby-forum.com/t/regular-expressions/49101/4 "2005-11-29T23:46:56Z")
On Nov 29, 2005, at 1:33 PM, Dmytro wrote: > Does anyone know how can I replace all [http://example.com](http://example.com) to [http://example.com](http://example.com) in text? > > * * * > > Rails mailing list > removed\_email\_address@domain.invalid > [http://lists.rubyonrails.org/mailman/listinfo/rails](http://lists.rubyonrails.org/mailman/listinfo/rails) Sure try this: text = “[http://example.com](http://example.com) what ever man\n another junk word http:// [www.example2.com](http://www.example2.com)” text.gsub!(/(http://\w\*.\*\w+.\w+\b)/){|url| “# {url}”} p text #=\> “[http://example.com](http://example.com) what ever man \n another junk word [http:// www.example2.com](http://www.example2.com)” That will do a substitution on all url’s in your text. It deals with [http://example.com](http://example.com) and [http://www.example.com](http://www.example.com). You will have to tweak the regex to get more than one subdomain to work though. Enjoy- -Ezra Z. Yakima Herald-Republic WebMaster [http://yakimaherald.com](http://yakimaherald.com) 509-577-7732 removed\_email\_address@domain.invalid ---
**Author:** ![mememe](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/977dab/32.png) [@mememe](https://www.ruby-forum.com/u/mememe)\ **Post date:** [November 29, 2005, 11:58pm UTC](https://www.ruby-forum.com/t/regular-expressions/49101/5 "2005-11-29T23:58:40Z")
me wrote: > Does anyone know how can I replace all [http://example.com](http://example.com) to [http://example.com](http://example.com) in text? Maybe you can try auto\_link helper [http://api.rubyonrails.com/classes/ActionView/Helpers/TextHelper.html#M000419](http://api.rubyonrails.com/classes/ActionView/Helpers/TextHelper.html#M000419) ---
**Author:** ![mememe](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/977dab/32.png) [@mememe](https://www.ruby-forum.com/u/mememe)\ **Post date:** [November 30, 2005, 12:55am UTC](https://www.ruby-forum.com/t/regular-expressions/49101/6 "2005-11-30T00:55:31Z")
On Tue, Nov 29, 2005 at 09:33:35PM +0000, Dmytro wrote: > Does anyone know how can I replace all [http://example.com](http://example.com) to [http://example.com](http://example.com) in text? sed ‘s%[http://example.com](http://example.com)%[http://example.com](http://example.com)%’ \< input \> output Of course, you may be looking for something more general, in which case you can specify a more complex regular expression (one which matches whatever you’re actually looking for, such as a general URL) inside parentheses, and then replace with ‘\1’. Ruby-wise, that should reduce to: output = input.gsub(/(http://[a-zA-Z/.?;%]+)/, ‘\1’) Caveat: The regular expression in there is _guaranteed_ to be incomplete; I just gave it as an example (which happens to match the example you gave, but not necessarily much more). A more complete regexp can be found at google://valid+url+regular+expression/, but be careful: not all of the examples you might find are equally correct… - Matt – “[the average computer user] has been served so poorly that he expects his system to crash all the time, and we witness a massive worldwide distribution of bug-ridden software for which we should be deeply ashamed.” – Edsger Dijkstra