How to keep the delimiters of Regex.Split?

Just put the pattern into a capture-group, and the matches will also be included in the result.

string[] result = Regex.Split("123.456.789", @"(\.)");

Result:

{ "123", ".", "456", ".", "789" }

This also works for many other languages:

• JavaScript: "123.456.789".split(/(\.)/g)
• Python: re.split(r"(\.)", "123.456.789")
• Perl: split(/(\.)/g, "123.456.789")

(Not Java though)

Say that input is "abc1defg2hi3jkl" and regex is to pick out digits.

String input = "abc1defg2hi3jkl";
var parts = Regex.Matches(input, @"\d+|\D+")
            .Cast<Match>()
            .Select(m => m.Value)
            .ToList();

Parts would be: abc 1 defg 2 hi 3 jkl

Use Matches to find the separators in the string, then get the values and the separators.

Example:

string input = "asdf,asdf;asdf.asdf,asdf,asdf";

var values = new List<string>();
int pos = 0;
foreach (Match m in Regex.Matches(input, "[,.;]")) {
  values.Add(input.Substring(pos, m.Index - pos));
  values.Add(m.Value);
  pos = m.Index + m.Length;
}
values.Add(input.Substring(pos));