Regular expression to find and remove duplicate words

Question

Using regular expressions in C#, is there any way to find and remove duplicate words or symbols in a string containing a variety of words and symbols?

Ex.

Answer 1

You won't be able to use regular expressions for this problem, because regex only matches regular languages. The pattern you are trying to match is context-sensitive, and therefore not "regular."

Fortunately, it is easy enough to write a parser. Have a look at Per Erik Stendahl's code.