Concatenate lists with LINQ

Question

Is it possible to concatenate a List<List<T>> into a List<T> with a single operation in a way which isn't horrible slow, i.e:

List<List<int>> listOfLists = new List<List<int>>();
List<int> concatenatedList = listOfLists.Something...

?

Actually, it IS called concatenation, msdn.microsoft.com/en-us/library/ee353462.aspx. — John Reynolds
– John Reynolds, Commented Aug 17, 2011 at 14:54

Andrey · Accepted Answer · 2011-01-19 11:22:56Z

28

listOfLists.SelectMany( l => l );

full line:

List<int> concatenatedList = listOfLists.SelectMany( l => l ).ToList();

answered Jan 19, 2011 at 11:15

Andrey

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Comments

Victor Haydin · Accepted Answer · 2011-01-19 11:20:57Z

0

Something like this:

listOfLists.Aggregate(new int[0], (res, list) => res.Concat(list));

answered Jan 19, 2011 at 11:20

Victor Haydin

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