Find-Replace pattern in C#

Question

I have a complex situation where I need to parse a very long string. I have to look for a pattern in the string and replace that pattern with another. I know I can simply use find/replace method but my case is bit different.

I have a string that contains the following pattern

#EPB_IMG#index-1_1.jpg#EPB_IMG


#EPB_IMG#index-1_2.jpg#EPB_IMG


#EPB_IMG#index-1_3.jpg#EPB_IMG


#EPB_IMG#index-1_4.jpg#EPB_IMG

and I want it to format as

#EPB_IMG#index-1_1.jpg|index-1_2.jpg|index-1_3.jpg|index-1_4.jpg#EPB_IMG

I don't know much about Regex and seeking for help.

Answer 1

Regex is overkill:

var parts = s.Split(new string[] { "#EPB_IMG", "#", "\n", "\r" }, StringSplitOptions.RemoveEmptyEntries);
var result = string.Join("|", parts);

Console.WriteLine("#EPB_IMG#" + result + "#EPB_IMG"); // prints your result.

Answer 2

Maybe something like this:

Expression: \\w+#(?<Image>(.+)\\.jpg)#\\w+

Replacement: ${Image}

Result: string.Format("#EPB_IMG#{0}#EPB_IMG", string.Join("|", listOfMatches))

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NOTE: Regex tested with: http://regexhero.net/tester/

Result is untested, but should work!

Answer 3

var result = "#EPB_IMG" + Regex.Matches(inputString, @"#EPB_IMG(.+)#EPB_IMG")
               .Cast<Match>()
               .Select(m => m.Groups[1].Value)
               .Aggregate((f, f2) => f + "|" + f2) + "#EPB_IMG";