How to check if list contains another list in same order

Question

Is there any simple way in c# to check if list consist of another list?. Here is example, I have:

var list1 = new List<int>() {1, 2, 3, 4, 5, 6,}; and second one var list2 = new List<int>() {5, 6};

this list is a part of first list so it should return true.

var list1 = new List<int>() {1, 2, 3, 4, 5, 6,}; and var list3 = new List<int>() {1, 3}; should return false.

It's not about checking if all elements in first list exist in second list but also about order. It has to have the same order.

Answer 1

This works for me:

public bool ContainsSubsequence<T>(List<T> sequence, List<T> subsequence)
{
    return
        Enumerable
            .Range(0, sequence.Count - subsequence.Count + 1)
            .Any(n => sequence.Skip(n).Take(subsequence.Count).SequenceEqual(subsequence));
}

This code uses Enumerable.Range to run through every possible starting point within sequence that could be the same as subsequence, and checks if the segment of sequence the same size as subsequence at this position is actually equal to subsequence.

So for this code:

var list1 = new List<int>() { 1, 2, 3, 4, 5, 6, };
var list2 = new List<int>() { 5, 6, };
var list3 = new List<int>() { 1, 3, };

Console.WriteLine(ContainsSubsequence(list1, list2));
Console.WriteLine(ContainsSubsequence(list1, list3));

I get:

True
False