Find index of an array in List of arrays in C#

Question

If you had a List of arrays like:

List<int[]> ListOfArrays = new List<int[]>();
ListOfArrays.Add(new int[] { 1, 1 });
ListOfArrays.Add(new int[] { 2, 1 });

How would you find the index of { 2, 1} in the List?

I do not want to use an iteration loop. I would like a concise method like the one suggested by PaRiMaL RaJ in Check if string array exists in list of string :

list.Select(ar2 => arr.All(ar2.Contains)).FirstOrDefault();

(the above code will return true if members of a given string array exist in a list of string arrays)

Answer 1

var myArr = new int[] { 2, 1 };
List<int[]> ListOfArrays = new List<int[]>();
ListOfArrays.Add(new int[] { 1, 1 });
ListOfArrays.Add(new int[] { 4, 1 });
ListOfArrays.Add(new int[] { 1, 1 });
ListOfArrays.Add(new int[] { 2, 1 });

int index = ListOfArrays.FindIndex(l => Enumerable.SequenceEqual(myArr, l));

Answer 2

You can use the SequenceEqual method for this. See MSDN: https://msdn.microsoft.com/en-us/library/vstudio/bb348567(v=vs.100).aspx

Answer 3

You can try this:

List<int[]> ListOfArrays = new List<int[]>();
ListOfArrays.Add(new int[] { 1, 1 });
ListOfArrays.Add(new int[] { 2, 1 });
var chk = ListOfArrays.FindIndex(e => (e.SequenceEqual(new int[] { 2, 1 })));