Split a string by double pipe.

How to split a string like "TEST1||TEST2".

I raised this question in C# MS newsgroup, and Tim Wilson answered my question that I should use

string[] asTest = Regex.Split(sTest, @"\|\|");

Well, this works beautifully. But it takes ome time for me to fully understand it. Fristly of all, "|" is considered one of the special characters (. $ ^ { [ ( | ) * + ? \) in the regular expression , so \ signals to the regular expression parser that the character following the backslash is not an operator. Then, how about string[] asTest = Regex.Split(sTest, "\|\|"), The compiler complains error CS1009: Unrecognized escape sequence. Will it make sense? According to MSDN , it means that "An unexpected character followed a backslash (\) in a string. The compiler expects one of the valid escape characters", then what is valid escape characters, | is a NOT a valid character following \, by using @ , we mean \| Unicode character 007C, do you understand, I am NOT.