Question

I have two hashsets that are loading data from two different text files.
The contents of both text files look as follows:

name/12441431252132
name1/323244231244142
name2/32423452524234

My code to currently load both files and make sure i only have unique results from textFile2:

HashSet<string> txt1 = new HashSet<string>(File.ReadLines("textFile1.txt"));
HashSet<string> txt2 = new HashSet<string>(File.ReadLines("textFile2.txt"));

txt2.ExceptWith(txt1); 

My problem is that it only removes lines based on the criteria if the whole line matches. I want to remove It based on the name basis instead. For example, name2 should never be included if its in textFile1 even if the id’s after the / are different.

How would i accomplish this?

Let me know if my explanation is not good i will try to improve it – and please excuse my english!

Answer 1

You can just add some string splitting to separate names and the rest of the content – the approach is a little “dirty” so in real code I would probably use foreach loops and introduce dedicated classes:

var content = File.ReadLines("textFile1.txt").Select(line => 
{
    var parts = line.Split('/');
    return new 
    { 
        Name = parts[0],
        Content = parts[1]
    };
});

HashSet<string> names = new HashSet<string>(content.Select(c=> c.Name));
HashSet<string> txt2 = new HashSet<string>(File.ReadLines("textFile2.txt"));
var uniques = txt2.Where(line => !names.Contains(line.Split('/')[0]));