How do i convert List<int[]> into List<int>

Question

private static void A(){
List<int[]> list = new List<int[]>();
int[] a = {0,1,2,3,4};
int[] b = {5,6,7,8,9};
list.Add(a);
list.Add(b);

List<int> list2 = new List<int>(); 
// list2 should contain {0,1,2,3,4,5,6,7,8,9}
}

How would i convert my List<int[]> list into a List<int> so that all the int[] arrays become one giant list of numbers

Answer 1

It looks like you might be looking for LINQ .SelectMany method. A quote from MSDN:

Projects each element of a sequence to an IEnumerable and flattens the resulting sequences into one sequence

List<int> list2 = list.SelectMany(l => l).ToList();

If you want numbers to be ordered in a specific order you could use .OrderBy before executing the query (which will be executed when we call .ToList )

List<int> list2 = list.SelectMany(l => l).OrderBy(i => i).ToList();

Answer 2

关于什么？

var list2 = a.Concat(b).ToList();

Answer 3

I would use the aggregate function. It is better when you have bigger collection.

List<int> list2 = list.Aggregate(new List<int>(), (ag, l) => { ag.AddRange(l); return ag; });