Question

I’d like to write an extension method for the .NET String class. I’d like it to be a special varation on the Split method – one that takes an escape character to prevent splitting the string when a escape character is used before the separator.

What’s the best way to write this? I’m curious about the best non-regex way to approach it.
Something with a signature like…

public static string[] Split(this string input, string separator, char escapeCharacter) {    // ... } 

UPDATE: Because it came up in one the comments, the escaping…

In C# when escaping non-special characters you get the error – CS1009: Unrecognized escape sequence.

In IE JScript the escape characters are throw out. Unless you try \u and then you get a ‘Expected hexadecimal digit’ error. I tested Firefox and it has the same behavior.

I’d like this method to be pretty forgiving and follow the JavaScript model. If you escape on a non-separator it should just ‘kindly’ remove the escape character.

Answer 1

How about:

public static IEnumerable<string> Split(this string input,                                          string separator,                                         char escapeCharacter) {     int startOfSegment = 0;     int index = 0;     while (index < input.Length)     {         index = input.IndexOf(separator, index);         if (index > 0 && input[index-1] == escapeCharacter)         {             index += separator.Length;             continue;         }         if (index == -1)         {             break;         }         yield return input.Substring(startOfSegment, index-startOfSegment);         index += separator.Length;         startOfSegment = index;     }     yield return input.Substring(startOfSegment); } 

That seems to work (with a few quick test strings), but it doesn’t remove the escape character – that will depend on your exact situation, I suspect.