C# / .NET equivalent for Java Matcher.find and Matcher.group

Question

I have seen that there are some posts regarding the Java Matcher class, but I was not able to find one regarding the specific methods find() and group().

I have this piece of code, where Lane and IllegalLaneException have already been defined:

private int getIdFromLane(Lane lane) throws IllegalLaneException {
    Matcher m = pattern.matcher(lane.getID());
    if (m.find()) {
        return Integer.parseInt(m.group());
    } else {
        throw new IllegalLaneException();
    }
}

Looking at the Java Documentation, we have the following:

find() - Attempts to find the next subsequence of the input sequence that matches the pattern.

group() - Returns the input subsequence matched by the previous match.

My question is, which is the equivalent to the methods find() and group() in C#?

EDIT: I forgot to say that I am using the MatchCollection class together with Regex

C# code:

private static Regex pattern = new Regex("\\d+$"); // variable outside the method

private int getIdFromLane(Lane lane) //throws IllegalLaneException
{
    MatchCollection m = pattern.Matches(lane.getID());
...
}

Gusman · Accepted Answer · 2016-05-10 11:06:04Z

1

On C# you will use Regex. Regex class has a function named "Matches" which will return all coincident matches for the pattern.

And each Match has a property called Groups where are stored captured groups.

So, find -> Regex.Matches, group -> Match.Groups.

They're not direct equivalents, but they will give you the same functionality.

Here is a simple example:

var reg = new Regex("(\\d+)$");

var matches = reg.Matches("some string 0123");

List<string> found = new List<string>();

if(matches != null)
{
    foreach(Match m in matches)
        found.Add(m.Groups[1].Value);
}

//do whatever you want with found

Remember that m.Groups[0] will contain the full capture and any subsequent Group will be captured groups.

Also, if you expect just one result then you can use .Match:

var match = reg.Match("some string 0123");

if(match != null && match.Success)
    //Process the Groups as you wish.

edited May 10, 2016 at 11:06

answered May 10, 2016 at 10:59

Gusman

15.2k2 gold badges38 silver badges53 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Terahertz Over a year ago

Mmm, Ok, I think I missunderstood the meaning of Regex.Matches at first! But then, if Regex.Matches is null, how could I handle it?

Gusman Over a year ago

That usually means there's no match at all. Let me post an example.

Gusman Over a year ago

Also, if you expect just one result you can use .Match, it will return just a match and you can chec .Success property of it to check if it was matched.

PhideasAmbrosianus · Accepted Answer · 2022-11-02 14:53:12Z

More complete example from @Gusman, I only made it easier cut/paste/understanding and including the required using statement. (I cannot edit, queue is full so doing this for future users...)

using System.Text.RegularExpressions;

public static void SampleRegexMatchesAndMatch()
{
  var reg = new Regex("(\\d+)$");

  //Example with Matches
  var matches = reg.Matches("some string 0123");

  List<string> found = new List<string>();

  foreach(Match m in matches)
    found.Add(m.Groups[1].Value);

  //Do whatever you want with found object results or work direct with matches
  //--------------------------------------------------------------------------

  //Example with Match
  var match = reg.Match("some string 0123");

  if(match != null && match.Success)
  {
    //Process the Groups as you wish.
  }
}

Collectives™ on Stack Overflow

C# / .NET equivalent for Java Matcher.find and Matcher.group

2 Answers 2

3 Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

3 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related