c# - Using Regex to determine if string contains a repeated sequence of a particular substring with comma separators and nothing else -

-

i want find if string contains repeated sequence of known substring (with comma separators) , nothing else , return true if case; otherwise false. example: substring "0,8"

string a: "0,8,0,8,0,8,0,8" returns true string b: "0,8,0,8,1,0,8,0" returns false because of '1'

i tried using c# string functions contains not suit requirements. totally new regular expression feel should powerful enough this. regex should use this?

the pattern string containing nothing repeated number of given substring (possibly 0 of them, resulting in empty string) \a(?:substring goes here)*\z. \a matches beginning of string, \z end of string, , (?:...)* matches 0 or more copies of matching thing between colon , close parenthesis.

but string doesn't match \a(?:0,8)*\z, because of commas; example match "0,80,80,80,8". need account commas explicitly \a0,8(?:,0,8)*\z.

you can build such thing in c# thus:

string oksubstring = "0,8"; string aok = "0,8,0,8,0,8,0,8"; string bok = "0,8,0,8,1,0,8,0";  regex okregex = new regex( @"\a" + oksubstring + "(?:," + oksubstring + @")*\z" ); okregex.ismatch(aok);  // true okregex.ismatch(bok);  // false

that hard-codes comma-delimiter; make more general. or maybe need literal regex. either way, that's pattern need.

edit changed anchors per mike samuel's suggestion.


Comments

Post a Comment

Popular posts from this blog

c# - SVN Error : "svnadmin: E205000: Too many arguments" -

-
i trying reposotries using c# code process svncommand = null; var psi = new processstartinfo("svnadmin"); psi.redirectstandardoutput = true; psi.redirectstandarderror = true; psi.useshellexecute = false; psi.arguments= @"dump c:\repositories\myrepo > c:\temp\myrepodumpfile.dump"; using (svncommand = process.start(psi)) { var myoutput = svncommand.standardoutput; var myerror = svncommand.standarderror; debug.write("output :" + environment.newline + environment.newline + myoutput.readtoend() + environment.newline + "error :" + environment.newline + environment.newline + myerror.readtoend()); svncommand.close(); } when use dump command commandline svnadmin dump c:\repositories\myrepo > c:\temp\myrepodumpfile.dump it works fine when try ...
Read more

c# - Copy ObservableCollection to another ObservableCollection -

-
how copy observablecollection item observablecollection without reference of first collection? here observablecollection item value changes affecting both collections. code private observablecollection<ratemodel> _allmetalrate = new observablecollection<ratemodel>(); private observablecollection<ratemodel> _metalrateondate = new observablecollection<ratemodel>(); public observablecollection<ratemodel> allmetalrate { { return this._allmetalrate; } set { this._allmetalrate = value; notifypropertychanged("metalrate"); } } public observablecollection<ratemodel> metalrateondate { { return this._metalrateondate; } set { this._metalrateondate = value; notifypropertychanged("metalrateondate"); } } foreach (var item in metalrateondate) allmetalrate.add(item); what causing , how can solve it? you need clone object referenced item before it's a...
Read more

All overlapping substrings matching a java regex -

-
is there api method returns (possibly overlapping) substrings match regular expression? for example, have text string: string t = 04/31 412-555-1235; , , have pattern: pattern p = new pattern("\\d\\d+"); matches strings of 2 or more characters. the matches are: 04, 31, 412, 555, 1235. how overlapping matches? i want code return: 04, 31, 41, 412, 12, 55, 555, 55, 12, 123, 1235, 23, 235, 35. theoretically should possible -- there obvious o(n^2) algorithm enumerates , checks substrings against pattern. edit rather enumerating substrings, safer use region(int start, int end) method in matcher . checking pattern against separate, extracted substring might change result of match (e.g. if there non-capturing group or word boundary check @ start/end of pattern). edit 2 actually, it's unclear whether region() expect zero-width matches. specification vague, , experiments yield disappointing results. for example: string line = "xx90xx"; strin...
Read more