How to take all but the last element in a sequence using LINQ?

Question

Let\'s say I have a sequence.

IEnumerable sequence = GetSequenceFromExpensiveSource();
// sequence now contains: 0,1,2,3,...,999999,1000000
         


        

Answer 1

Nothing in the BCL (or MoreLinq I believe), but you could create your own extension method.

public static IEnumerable TakeAllButLast(this IEnumerable source)
{
    using (var enumerator = source.GetEnumerator())
        bool first = true;
        T prev;
        while(enumerator.MoveNext())
        {
            if (!first)
                yield return prev;
            first = false;
            prev = enumerator.Current;
        }
    }
}