# The easiest way to separate substrings from a line string **URL:** \ **Category:** Ruby\ **Created:** [July 9, 2009, 12:12pm UTC](https://www.ruby-forum.com/t/the-easiest-way-to-separate-substrings-from-a-line-string/171795 "2009-07-09T12:12:01Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![thriving](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/ecae2f/32.png) [@thriving](https://www.ruby-forum.com/u/thriving)\ **Post date:** [July 9, 2009, 12:12pm UTC](https://www.ruby-forum.com/t/the-easiest-way-to-separate-substrings-from-a-line-string/171795/1 "2009-07-09T12:12:01Z")
I have working on tag system and There is information like this “important urgent project 2009” i want to seperate into word, one word at the time is okay What is the easiest way to separate those string word by word, space between each word might has more than 1. My idea is to use loop to check character by character that it is space or not, and then cut the part, but i thought it might have easier way that i don’t know Thank you in advance ---
**Author:** ![thriving](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/ecae2f/32.png) [@thriving](https://www.ruby-forum.com/u/thriving)\ **Post date:** [July 9, 2009, 12:17pm UTC](https://www.ruby-forum.com/t/the-easiest-way-to-separate-substrings-from-a-line-string/171795/2 "2009-07-09T12:17:12Z")
Hi – On Thu, 9 Jul 2009, Sarawut Poaitwinyu wrote: > or not, and then cut the part, but i thought it might have easier way > that i don’t know words = string.split When you call split with no argument, it splits on whitespace (including more than one character). David ---
**Author:** ![thriving](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/ecae2f/32.png) [@thriving](https://www.ruby-forum.com/u/thriving)\ **Post date:** [July 9, 2009, 12:21pm UTC](https://www.ruby-forum.com/t/the-easiest-way-to-separate-substrings-from-a-line-string/171795/3 "2009-07-09T12:21:54Z")
David A. Black wrote: > Hi – > > On Thu, 9 Jul 2009, Sarawut Poaitwinyu wrote: > > > or not, and then cut the part, but i thought it might have easier way > > that i don’t know > > words = string.split > > When you call split with no argument, it splits on whitespace > (including more than one character). > > David ``` Thank you , i will try ``` ---
**Author:** ![thriving](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/ecae2f/32.png) [@thriving](https://www.ruby-forum.com/u/thriving)\ **Post date:** [July 9, 2009, 6:07pm UTC](https://www.ruby-forum.com/t/the-easiest-way-to-separate-substrings-from-a-line-string/171795/4 "2009-07-09T18:07:30Z")
2009/7/9 David A. Black [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid): > > What is the easiest way to separate those string word by word, space > > between each word might has more than 1. > > > > My idea is to use loop to check character by character that it is space > > or not, and then cut the part, but i thought it might have easier way > > that i don’t know > > words = string.split > > When you call split with no argument, it splits on whitespace > (including more than one character). I am more like the “positive” guy - meaning explicitly defining what I want returned. I would do words = string.scan /\w+/ That way dot, question mark and other signs won’t hurt. It may not make a difference but it’s probably good to see different approaches. Kind regards robert ---
**Author:** ![thriving](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/ecae2f/32.png) [@thriving](https://www.ruby-forum.com/u/thriving)\ **Post date:** [July 9, 2009, 6:52pm UTC](https://www.ruby-forum.com/t/the-easiest-way-to-separate-substrings-from-a-line-string/171795/5 "2009-07-09T18:52:01Z")
Hi – On Fri, 10 Jul 2009, Robert K. wrote: > > > > > > > (including more than one character). > > I am more like the “positive” guy - meaning explicitly defining what I > want returned. I would do > > words = string.scan /\w+/ > > That way dot, question mark and other signs won’t hurt. It may not > make a difference but it’s probably good to see different approaches. string.split does explicitly define what I want back; it’s just something different from what you want back 🙂 It depends exactly how you define “word”. I was assuming it was /\S+/ but it may indeed be /\w+/ (or maybe /[^\W\d\_]+/ or something). David ---
**Author:** ![thriving](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/ecae2f/32.png) [@thriving](https://www.ruby-forum.com/u/thriving)\ **Post date:** [July 9, 2009, 10:41pm UTC](https://www.ruby-forum.com/t/the-easiest-way-to-separate-substrings-from-a-line-string/171795/6 "2009-07-09T22:41:42Z")
2009/7/9 David A. Black [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid): > On Fri, 10 Jul 2009, Robert K. wrote: > > > 2009/7/9 David A. Black [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid): > > > > > On Thu, 9 Jul 2009, Sarawut Poaitwinyu wrote: > > That way dot, question mark and other signs won’t hurt. It may not > > make a difference but it’s probably good to see different approaches. > > string.split does explicitly define what I want back; it’s just > something different from what you want back 🙂 That’s true. I just wanted to make the point that there are these two major approaches: define positively what you want in your result or define it ex negativo, i.e. state what you want to use as separator. The whole point is that both approaches may behave identical with the original set of test data but will exhibit different behavior as soon as the input changes. If you use #split, you might get something you did not want in the first place. With #scan you won’t notice - which could be bad as well. The super safe variant would be to first do a match on the whole string to ensure it does contain expected data only and fail if not. After that it does not matter any more what extraction method one uses. > It depends exactly how > you define “word”. I was assuming it was /\S+/ but it may indeed be > /\w+/ (or maybe /[^\W\d\_]+/ or something). Absolutely. Kind regards robert ---
**Author:** ![thriving](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/ecae2f/32.png) [@thriving](https://www.ruby-forum.com/u/thriving)\ **Post date:** [July 13, 2009, 3:47am UTC](https://www.ruby-forum.com/t/the-easiest-way-to-separate-substrings-from-a-line-string/171795/7 "2009-07-13T03:47:23Z")
Thank you for everyone again, it seems that you guys discussed sort of regular expression that i didn’t understand but thank you for it anyone, i will try to research about it later ---
**Author:** ![thriving](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/ecae2f/32.png) [@thriving](https://www.ruby-forum.com/u/thriving)\ **Post date:** [July 13, 2009, 11:48am UTC](https://www.ruby-forum.com/t/the-easiest-way-to-separate-substrings-from-a-line-string/171795/8 "2009-07-13T11:48:51Z")
Hi – On Mon, 13 Jul 2009, Dave B. wrote: > Moving off-topic from the thread, but David Black wrote: > > > … /\w+/ (or maybe /[^\W\d\_]+/ or something). > > Do people actually say /[^\W\d\_]/ instead of /[a-z]/i? The latter is > much easier for me to read. Does the former include non-latin > word-characters? Yes: > > s = “\u00e9” > > =\> “é” > > > /\w/.match(s) > > =\> #\ > > > /[a-z]/.match(s) > > =\> nil Another choice would be: /[[:alpha:]]/ which I believe would do the same thing that my character class did (unless there are some exclusions, inclusions, or edge cases I’m not remembering). David ---
**Author:** ![thriving](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/ecae2f/32.png) [@thriving](https://www.ruby-forum.com/u/thriving)\ **Post date:** [July 13, 2009, 5:11am UTC](https://www.ruby-forum.com/t/the-easiest-way-to-separate-substrings-from-a-line-string/171795/9 "2009-07-13T05:11:38Z")
Moving off-topic from the thread, but David Black wrote: > … /\w+/ (or maybe /[^\W\d\_]+/ or something). Do people actually say /[^\W\d\_]/ instead of /[a-z]/i? The latter is much easier for me to read. Does the former include non-latin word-characters? Cheers, Dave B.