C# Regex, extract strings by reference string

Question

Edit: Solution by @Heinzi https://stackoverflow.com/a/1731641/87698

I got two strings, for example someText-test-stringSomeMoreText? and some kind of pattern string like this one {0}test-string{1}?.

I'm trying to extract the substrings from the first string that match the position of the placeholders in the second string.

The resulting substrings should be: someText- and SomeMoreText.

I tried to extract with Regex.Split("someText-test-stringSomeMoreText?", "[.]*test-string[.]*\?". However this doesn't work.

I hope somebody has another idea...

There's nothing built-in in the framework, but someone already implemented an algorithm to do that: http://stackoverflow.com/a/1731641/87698 — Heinzi, Oct 29 '13 at 14:59
possible duplicate of [Parsing formatted string](http://stackoverflow.com/questions/1410012/parsing-formatted-string) — Heinzi, Oct 29 '13 at 15:06

Alex Filipovici · Answer 1 · 2013-10-29T11:22:48.783

0

One option you have is to use named groups:

(?<prefix>.*)test-string(?<suffix>.*)\?

This will return 2 groups containing the wanted prefix and the suffix.

var match = Regex.Match("someText-test-stringSomeMoreText?", 
    @"(?<prefix>.*)test-string(?<suffix>.*)\?");
Console.WriteLine(match.Groups["prefix"]);
Console.WriteLine(match.Groups["suffix"]);

edited Oct 29 '13 at 11:22

answered Oct 29 '13 at 11:17

Alex Filipovici

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The problem is, those two input strings are completely variable. The second string could also look like `{0}test{1}stringSome{2}Text?` for example. The problem is, I'm looking for a way to create a working regex pattern from this pseudo pattern string dynamicaly. – Matthias Oct 29 '13 at 11:44

score 0 · Answer 2 · answered Oct 29 '13 at 14:53

I got a solution, at least its a bit dynamical.

First I split up the pattern string {0}test-string{1}? with string[] patternElements = Regex.Split(inputPattern, @"(\\\{[a-zA-Z0-9]*\})");

Then I spit up the input string someText-test-stringSomeMoreText? with string[] inputElements = inputString.Split(patternElements, StringSplitOptions.RemoveEmptyEntries);

Now the inputElements are the text pieces corresponding to the placeholders {0},{1},...

C# Regex, extract strings by reference string

2 Answers2