Posted on 2006-07-06
Last Modified: 2011-09-20
Hello...could some1 plz tell me the regular expression to extract numbers from text files in C#. Number could be of any size with commas occuring at different positions. A few examples of the number formats could be as follows

i have tried for a week with diff expressions  and am not getting it,
Question by:jhav1594
  • 3
LVL 15

Expert Comment

ID: 17051768
Try one of these:

1. Optional minus sign value from 0 to 999,999,999 with option decimal places
      Regex rx = new Regex(@"-?(\d{1-3},){0-2}\d{1-3}(\.\d+)?");

2. Same as the above, but with no minus sign:
      Regex rx = new Regex(@"(\d{1-3},){0-2}\d{1-3}(\.\d+)?");

3. Same as #2 but no decimals:
      Regex rx = new Regex(@"(\d{1-3},){0-2}\d{1-3}");

You use it like:

        MatchCollection matches = rx.Matches(text);
        foreach (Match match in matches)
             [process the matching string]

LVL 15

Expert Comment

ID: 17051784
Just thinking about it - this regexp will allow numbers like 123,456,7 which isn't what you want, so the expression should be:


Author Comment

ID: 17052613
hey thanks...but this isnt working for didnt match up...any ideas what mite be going wrong...
LVL 15

Accepted Solution

bpmurray earned 250 total points
ID: 17053261
I must have been asleep when I did that  - apologies!

Regex rx = new Regex(@"((\d{1,3},){0,2}\d{3})|(\d{1,2})");

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