CODEWITHSUNDEEP
c#regex
Egert Aia
Egert Aia

Reputation: 469

Advanced Regex for splitting strings

I am trying to write an advanced regrex that will split my string in correct places.

Do you remember the old phones (T9), where you could simply do 22022 to write 'bb' I need something similiar.

I got the splitting at the whitespaces(which implement the pause), but the rest is really hard.

For whitespace it is

var l = Regex.Split(a, @"\s");

but i would need following:44204420442 should be 44, 2, 0, 44, 2, 0, 44, 2 so it would split also after the character is changed compared to the previous one.

Thank you in advance!

Upvotes: 2

Views: 115

Answers (2)

Dmitrii Bychenko
Dmitrii Bychenko

Reputation: 186678

Instead of complex regular expression you can implement a simple loop:

public static IEnumerable<String> MySplit(String value) {
  if (null == value)
    throw new ArgumentNullException("value");

  char prior = '\0';

  StringBuilder sb = new StringBuilder();

  foreach (char current in value) {
    if (sb.Length != 0 && prior != current) {
      yield return sb.ToString();

      sb.Clear();
    }

    if (!Char.IsWhiteSpace(current))
      sb.Append(current);

    prior = current;
  }

  if (sb.Length > 0)
    yield return sb.ToString();
}

Test:

string value = "44204420442";
string[] parts = MySplit(value).ToArray(); // if you want an array

// 44, 2, 0, 44, 2, 0, 44, 2
Console.Write(String.Join(", ", parts));

string value2 = "44 44 42";

// 44, 44, 4, 2
Console.Write(String.Join(", ", MySplit(value2)));

Upvotes: 1

Tim Pietzcker
Tim Pietzcker

Reputation: 336138

Instead of splitting, it's easier to collect all the matches:

Regex regexObj = new Regex(@"(\d)\1*");
allMatchResults = regexObj.Matches(subjectString);

You need to look at each Match object's .Groups[0].Value to get the entire match.

Upvotes: 4

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