Question

I’m wondering if my method below of comparing an array of strings (or any simple type really) has any performance repercussions.

bool AreValuesEqual(List<string> oldFieldValue, List<string> newFieldValue)
    {
        if (oldFieldValue.Count != newFieldValue.Count)
            return false;

        var list1 = oldFieldValue;
        list1.AddRange(newFieldValue);
        var list2 = list1.Distinct();
        return list2.Count() == newFieldIds.Count;
    }

I don’t know how intensive Distinct() will be for this, but I think it shouldn’t be too much compared to another loop.

Edit – Sorry, should have provided more background info. Couple things:

-There will be no duplicates in the parameter arrays.

-I’m not really concerned about order, I just want to know if the values in one array is the same as the other array. If the other array has a different value, return false.

Answer 1

I don’t think there’s a significant performance issue with your code. However, what bothers me a little is that you’re modifying list1 as a side-effect of doing the comparison.

Will the following work better?

if(list1.Count == list2.Count)
{
    var list3 = list1.Intersect(list2);
    return list3.Count == list1.Count();
}

A similar question was posted at Compare two Lists for differences.