CODEWITHSUNDEEP
c#compare
zrabzdn
zrabzdn

Reputation: 995

Compare two List<string> by value and index

I have two string collections and need to return any string value if the value doesn't exist in collection and index of value not equals. I implement with not exists condition, but I don't know add condition for index not equals.

public IEnumerable<string> GetInvalidHeaders(IEnumerable<string> list1, List<string> list2)
{            
     return list1.Where(header => list2 == null
                               || list2.All(x => x != header));
}

Values of collections must unique by value and index

Upvotes: 0

Views: 3754

Answers (2)

Tim Schmelter
Tim Schmelter

Reputation: 460098

This accepts not only strings and uses deferred execution:

public IEnumerable<T> GetDifferences<T>(IList<T> seq1, IList<T> seq2)
{
    for (int i = 0; i < seq1.Count; i++)
    {
        T item1 = seq1[i];
        if (i >= seq2.Count)
            yield return item1;
        else
        {
            T item2 = seq2[i];
            if (!object.ReferenceEquals(item1, item2))
            {
                if (item1 == null || item2 == null)
                    yield return item1;
                else if (!item1.Equals(item2))
                    yield return item1;
            }
        }
    }
}

Usage: 

var diff = GetDifferences(list1, list2);

Upvotes: 2

krimog
krimog

Reputation: 1276

public IEnumerable<string> GetDifferences(List<string> list1, List<string> list2)
{
    for (int i = 0; i < list1.Count; i++)
    {
        if (list1[i] != list2[i]) yield return list1[i];
    }
}

Do you need something like that ?

Upvotes: 4

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