# Regex help partial code **URL:** \ **Category:** Ruby\ **Created:** [January 13, 2008, 10:30pm UTC](https://www.ruby-forum.com/t/regex-help-partial-code/125928 "2008-01-13T22:30:59Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![Junkone](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e274bd/32.png) [@Junkone](https://www.ruby-forum.com/u/Junkone)\ **Post date:** [January 13, 2008, 10:30pm UTC](https://www.ruby-forum.com/t/regex-help-partial-code/125928/1 "2008-01-13T22:30:59Z")
Hello I have with great effort started on teh regex implemention and am stuck at one point. here is my code (add)\s+\S+\s+[i|s|f]\s+[pei]?\s+ The string is as follows and the tokens are equavalent to 1 token=Add 2 token=any text 3. token=one of the following i or s or f 4.token= 0 or 1 of the following characters [p e i] I am stuck at the 4th token. i thought ? after the token will give the 0 or 1 option. pl correct me if i made a error seede ---
**Author:** ![Junkone](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e274bd/32.png) [@Junkone](https://www.ruby-forum.com/u/Junkone)\ **Post date:** [January 14, 2008, 12:45am UTC](https://www.ruby-forum.com/t/regex-help-partial-code/125928/2 "2008-01-14T00:45:50Z")
On Jan 13, 4:25 pm, Junkone [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > 4.token= 0 or 1 of the following characters [p e i] > > I am stuck at the 4th token. i thought ? after the token will give > the 0 or 1 option. > pl correct me if i made a error > > seede irb(main):046:0\> a=Regexp.new(‘(add)\s+(\S+)\s+([i|s|f])\s+([pei])?\s +’,true) =\> /(add)\s+(\S+)\s+([i|s|f])\s+([pei])?\s+/i irb(main):047:0\> a =~(“Add comp i pe”) =\> nil I dont get match at 4th token ---
**Author:** ![Junkone](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e274bd/32.png) [@Junkone](https://www.ruby-forum.com/u/Junkone)\ **Post date:** [January 14, 2008, 7:25am UTC](https://www.ruby-forum.com/t/regex-help-partial-code/125928/3 "2008-01-14T07:25:38Z")
On Jan 13, 5:41 pm, Junkone [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > The string is as follows and the tokens are equavalent to > > irb(main):046:0\> a=Regexp.new(‘(add)\s+(\S+)\s+([i|s|f])\s+([pei])?\s > +’,true) > =\> /(add)\s+(\S+)\s+([i|s|f])\s+([pei])?\s+/i > irb(main):047:0\> a =~(“Add comp i pe”) > =\> nil > > I dont get match at 4th token There are a few problems here, I think. Regexp.new(‘(add)\s+(\S+)\s+([i|s|f])\s+([pei])?\s+’,true) As written, the second token can’t have whitespace. Is that what you intended? You want ([isf]) for your third token. That will match a single instance of one of the three characters. Also, I’m not clear on what you want for the fourth token. Do you want 0 or 1 of [pei] or 0 or 1 of _each_ of [pei] - which of these are valid for the fourth token: e or pe. You should also end the regex with \s\* unless there’s always going to be whitespace. You’re currently checking for one or more whitespace characters at the end, but your test didn’t have any. Assuming you do allow 0 or 1 of each of [pei] for the fourth token and 0 or more whitespace characters at the end, I would use: r = /(add)\s+(\S+)\s+([isf])\s+(p?e?i?)\s\*/i Though, if there can’t be whitespace in any of the tokens, you might want to use split rather than a regex. The regex above can only get the fourth token right if the letters are in order - p will match, ei will match, ip will not. Split wouldn’t have that problem. There may be a regex way around that, but I can’t think of it at the moment. “Add comp i ep”.scan r # =\> [[“Add”, “comp”, “i”, “e”]] “Add comp i ep”.split # =\> [“Add”, “comp”, “i”, “ep”] ---
**Author:** ![Junkone](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e274bd/32.png) [@Junkone](https://www.ruby-forum.com/u/Junkone)\ **Post date:** [January 14, 2008, 4:52pm UTC](https://www.ruby-forum.com/t/regex-help-partial-code/125928/4 "2008-01-14T16:52:14Z")
On Mon, 14 Jan 2008, Junkone wrote: > Hello > I have with great effort started on teh regex implemention and am > stuck at one point. > here is my code > (add)\s+\S+\s+[i|s|f]\s+[pei]?\s+ > > The string is as follows and the tokens are equavalent to > 1 token=Add Unless you use the i modifier, ruby regexps are case sensitive. So /add/ won’t match /Add/, but /add/i will. > 2 token=any text > 3. token=one of the following i or s or f You want /[isf]/ /[i|s|f]/ is probably equivalent to /[isf|]/ > 4.token= 0 or 1 of the following characters [p e i] > /[pei]?/ > I am stuck at the 4th token. i thought ? after the token will give > the 0 or 1 option. > It does. > pl correct me if i made a error Show the exact regexp and the string it failed on. John C. Phone : (64)(3) 358 6639 Tait Electronics Fax : (64)(3) 359 4632 PO Box 1645 Christchurch Email : removed\_email\_address@domain.invalid New Zealand ---
**Author:** ![Junkone](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e274bd/32.png) [@Junkone](https://www.ruby-forum.com/u/Junkone)\ **Post date:** [January 14, 2008, 7:00pm UTC](https://www.ruby-forum.com/t/regex-help-partial-code/125928/5 "2008-01-14T19:00:10Z")
On Mon, 14 Jan 2008, Junkone wrote: > irb(main):046:0\> a=Regexp.new(’(add)\s+(\S+)\s+([i|s|f])\s+([pei])?\s > +’,true) > =\> /(add)\s+(\S+)\s+([i|s|f])\s+([pei])?\s+/i > irb(main):047:0\> a =~(“Add comp i pe”) > =\> nil > > I dont get match at 4th token irb irb(main):002:0\> /(add)\s+(\S+)\s+([i|s|f])\s+([pei])?\s+/i =~ “Add comp i pe” =\> nil irb(main):003:0\> /(add)\s+(\S+)\s+([i|s|f])\s+([pei])?/i =~ “Add comp i pe” =\> 0 The last \s+ insists on matching one or more whitespace chars. Here is a general recipe for solving this class of problems… Set up a simple test like I have above… Delete elements out of the regex until it matches. The problem was the last one you deleted. John C. Phone : (64)(3) 358 6639 Tait Electronics Fax : (64)(3) 359 4632 PO Box 1645 Christchurch Email : removed\_email\_address@domain.invalid New Zealand