CODEWITHSUNDEEP
c#sqllinq
Lobuno
Lobuno

Reputation: 1405

C# ignoring "duplicates" in a data table

I have a datatable from some source which the structor

bookid title author

The table can contain the same book (repeated) if the book has several authors. Like

Book id    title    author    
32         Book1    P. Samsom
45         Book34   R. Englund
45         Book34   H. Granger
56         Book45   F. Lister

etc.

Now the second and third book are the same ( it has 2 authors). When displaying the table (which can contain thousands items) I don't want to display the same book twice or more. It 's just enough with displaying one of them (I don't care).

Doing a Select distinct on the table won't help here. Doing a select distinct ignoring the author works, but I need at least ONE author. So what I want to do is to find the most effective way to just create a new table or view from this one which ignores any "duplicated" item keeping at least one author.

Any ideas?

Upvotes: 1

Views: 161

Answers (3)

Zen
Zen

Reputation: 244

DistinctBy from MoreLINQ

var results = books.DistinctBy(x => x.title).ToList();

Upvotes: 0

L.B
L.B

Reputation: 116108

var result =  books.GroupBy(b => b.bookid)
                   .Select(g => 
                        new { 
                            id = g.Key, 
                            title = g.First().title, 
                            authors = g.Select(a=>a.author).ToList() 
                        })
                   .ToList();

Upvotes: 0

Saeed Amiri
Saeed Amiri

Reputation: 22555

var books = Books.GroupBy(x=>x.Title).Select(x=>x.First()).ToList();

Upvotes: 3

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