CODEWITHSUNDEEP
c#
M. Mohebbi
M. Mohebbi

Reputation: 27

How to find a one dimensional array in a two dimensional array in C#

I have a two dimensional array namely States. I create a one dimensional array, say SubState. Then I change SubState. I want to find new SubState in States and get the index. As an example:

int[][] States = new int[3][] { new int[] { 3, 3, 4 }, new int[] { 2, 5, 1 }, new int[] { 2, 3, 4 } };
int[] SubState = new int[States[0].Length];
States[0].CopyTo(SubState, 0);
SubState[0] -= 1;

I want to find the index of new SubState in State, which will be 2 in the example. Thanks.

Upvotes: 1

Views: 94

Answers (3)

HashPsi
HashPsi

Reputation: 1391

You can use Linq:

  var index = -1;

  var foundSubState = States.FirstOrDefault(x => {
    index++;
    return x.SequenceEqual(SubState);
  });

  var res = foundSubState != default(Array) ? index : -1;

Upvotes: 0

Sergey Kalinichenko
Sergey Kalinichenko

Reputation: 726559

You can use SequenceEqual method inside a LINQ query, like this:

var nextStateIndex = States
    .Select((a, i) => new {Index = i, Array = a})
    .FirstOrDefault(p => p.Array.SequenceEqual(SubState))
    ?.Index;
if (nextStateIndex.HasValue) {
    ...
}

Note: this code uses the new ?. operator. If you are targeting C# version that does not have support for this operator, store FirstOrDefault result for an explicit null checking.

Upvotes: 0

Douglas
Douglas

Reputation: 54887

You're looking for SequenceEqual:

int index = -1;
for (int i = 0; i < States.Length; i++)
    if (States[i].SequenceEqual(SubState))
    {
        index = i;
        break;
    }

If you define a LINQ FindIndex operator, you can express it more concisely using:

int index = States.FindIndex(s => s.SequenceEqual(SubState));

Upvotes: 1

Related Questions