Extract a word from string using regex

Question

I have c# code in which I run a perl file using commandline and capture that output in a c# string. I want to extract a certain word from this string using regex. I tried several methods to capture that specific word but it didnt work.

For example: the below text was captured in a string in c#

CMD.EXE was started with the above path as the current directory.
UNC paths are not supported. Defaulting to Windows directory.
Initializing.
jsdns jsdnjs wuee uwoqw duwhduwd 9-8 is = COM10
uuwe sodks asjnjx

In the above code I want to extract COM10. Similarly this value can also change to COM12 or COM8 or COM15. I will always have COM in the text but the succeeding number can change.

Can someone let me know how to go about with regex. I used RegexOptions.Multiline but am not sure how to go about it. Also if an explanation is included it would be helpful.

hwnd · Accepted Answer · 2014-08-13 03:12:55Z

6

You can use the following regex.

Match m = Regex.Match(input, @"\b(?i:com\d+)");
if (m.Success)
    Console.WriteLine(m.Value); //=> "COM10"

Explanation:

\b       # the boundary between a word character (\w) and not a word character
(?i:     # group, but do not capture (case-insensitive)
  com    #   'com'
  \d+    #   digits (0-9) (1 or more times)
)        # end of grouping

Working Demo

edited Aug 13, 2014 at 3:12

answered Aug 13, 2014 at 3:07

hwnd

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Tyress · Accepted Answer · 2014-08-13 03:07:54Z

1

string thestring = @"CMD.EXE was started with the above path as the current directory. 
UNC paths are not supported. Defaulting to Windows directory. 
Initializing. 
jsdns jsdnjs wuee uwoqw duwhduwd 9-8 is = COM10 
uuwe sodks asjnjx";

string matchedString = Regex.Match(thestring,@"COM[\d]+").Value;

The Regex that is matched against the string (COM[\d]+) means:

match an instance of COM followed by at least one instance (+) of a digit (\d)

This is assuming there is only one instance of COM(NUMBER) in your string.

You can also put a space to make sure that only space COM is matched by the Regex, like so:

string matchedString = Regex.Match(thestring,@"\sCOM[\d]+").Value;

edited Aug 13, 2014 at 3:07

answered Aug 13, 2014 at 2:59

Tyress

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1 Comment

Braj Over a year ago

use \b before COM to match only COM instead of XCOM

Federico Piazza · Accepted Answer · 2014-08-13 03:21:09Z

1

You can use a regex like this:

\b(COM\d+)\b

Working demo

enter image description here

answered Aug 13, 2014 at 3:21

Federico Piazza

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