If what you want is a list of distinct artist values from that list then forget the stuff that isn’t the artist. Just get the artist values and call
Dim distinctArtists = File.ReadLines(filePath). Select(Function(s) s.Split(","c)(IDX_ARTIST)). Distinct(). ToArray()
Notice the call to
ReadLines rather than
ReadLines should be the default and you should only use
ReadAllLines when you need random/multiple access to the resulting array.
I tend to prefer function syntax but, if you prefer query syntax, that would look like this:
Dim distinctArtists = (From s In File.ReadLines(filePath) Select s.Split(","c)(IDX_ARTIST) Distinct).ToArray()
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