Accepted answer

If you want to treat the arrays as "sets" and ignore order and duplicate items, you can use HashSet<T>.SetEquals method:

var isEqual = new HashSet<int>(first).SetEquals(second);

Otherwise, your best bet is probably sorting both sequences in the same way and using SequenceEqual to compare them.


This should help:

    IEnumerable<int> data = new []{ 3,5,6,9 };
    IEnumerable<int> otherData = new[] {6, 5, 9, 3};

    if(data.All(x => otherData.Contains(x)))
        //Code Goes Here


First check if both data collections have the same number of elements and the check if all the elements in one collection are presented in the other

        IEnumerable<int> data = new[] { 3, 5, 6, 9 };
        IEnumerable<int> otherData = new[] { 6, 5, 9, 3 };

        bool equals = data.Count() == otherData.Count() && data.All(x => otherData.Contains(x));


  1. First, check the length. If they are different, the sets are different.
  2. you can do data.Intersect(otherData);, and check the length is identical.
  3. OR, simplt sort the sets, and iterate through them.


Here is another way to do it:

IEnumerable<int> data = new[] { 3, 5, 6, 9 };
IEnumerable<int> otherData = new[] { 6, 5, 9, 3 };

data = data.OrderBy(d => d);
otherData = otherData.OrderBy(d => d);
data.Zip(otherData, (x, y) => Tuple.Create(x, y)).All(d => d.Item1 == d.Item2);


If you might have duplicates (or if you want a solution which performs better for longer lists), I'd try something like this:

static bool IsSame<T>(IEnumerable<T> set1, IEnumerable<T> set2)
    if (set1 == null && set2 == null)
        return true;
    if (set1 == null || set2 == null)
        return false;

    List<T> list1 = set1.ToList();
    List<T> list2 = set2.ToList();

    if (list1.Count != list2.Count)
        return false;


    return list1.SequenceEqual(list2);

UPDATE: oops, you guys are right-- the Except() solution below needs to look both ways before crossing the street. And it has lousy perf for longer lists. Ignore the suggestion below! :-)

Here's one easy way to do it. Note that this assumes the lists have no duplicates.

bool same = data.Except (otherData).Count() == 0;


I suggest sorting both, and doing an element-by-element comparison.

data.OrderBy(x => x).SequenceEqual(otherData.OrderBy(x => x))

I'm not sure how fast the implementation of OrderBy is, but if it's a O(n log n) sort like you'd expect the total algorithm is O(n log n) as well.

For some cases of data, you can improve on this by using a custom implementation of OrderBy that for example uses a counting sort, for O(n+k), with k the size of the range wherein the values lie.

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