Comments on: Remove Duplicate Lines From A Text File Using LINQ

By: Rob

Rob — Wed, 08 Sep 2010 19:14:25 +0000

Bah, it occurs to me that GetHashCode should probably be implemented as a.Substring(a.LastIndexOf(‘,’) + 1).GetHashCode() – but I’m sure you get the point. Cheers!

By: Rob

Rob — Wed, 08 Sep 2010 19:12:48 +0000

For simply duplicate lines, you could easily do:

File.WriteAllLines(path, File.ReadAllLines(path).Distinct());

For your problem, I’d suggest that a simpler method might be available, since you’re already creating another class:
public class ErrorEqualityComparer : IEqualityComparer {
public bool Equals(string a, string b) {
return a.Substring(a.LastIndexOf(‘,’) + 1) == b.Substring(b.LastIndexOf(‘,’));
}
public int GetHashCode(string a) { return a.GetHashCode(); }
}

Now I can call:
File.WriteAllLines(path, File.ReadAllLines(path).Reverse().Distinct(new ErrorEqualityComparer()).Reverse());

This is certainly less LINQ-y, but it makes convenient use of extension methods. :)

Thanks for the blog – helped me find an answer I needed for master/detail data.

By: Liran

Liran — Sat, 27 Dec 2008 21:24:58 +0000

in the method ReadFileIntoCollection, whats the point by doing
var query = from e in (linq the retrievs collection) select e ?

couldn’t you just do it like this:
var query = linq the retrievs collection
?

Thank you.