How could I take 1 more item from Linq's TakeWhile?

Question

(line of code of interest is the last one, the rest is just for a full representation)

Using the following code, I wanted to take VOTERS until I exceeded the maximum votes needed, but it stops right before reaching that maximum number of votes, so my voters pool has 1 fewer voter than I wanted.

Is there a clean way in LINQ where I could have made it take votes UNTIL it reached the maximum numbers of votes? I know I could add one more voter or do this in a loop but I am curious if there was a good way to do this with LINQ instead.

var voters = new List<Person>
                             {
                                 new Person("Alice", Vote.Yes ),
                                 new Person("Bob", Vote.Yes),
                                 new Person("Catherine", Vote.No),
                                 new Person("Denzel", Vote.Yes),
                                 new Person("Einrich", Vote.Abstain),
                                 new Person("Frederica", Vote.Abstain),
                                 new Person("Goeffried", Vote.Abstain),
                             };
            voters.Single(c => c.Name == "Alice").Voices = 100;
            voters.Single(c => c.Name == "Bob").Voices = 150;
            voters.Single(c => c.Name == "Catherine").Voices = 99;
            voters.Single(c => c.Name == "Denzel").Voices = 24;
            voters.Single(c => c.Name == "Einrich").Voices = 52;
            voters.Single(c => c.Name == "Frederica").Voices = 39;
            voters.Single(c => c.Name == "Goeffried").Voices = 99;

// this takes voters until we are BEFORE reaching X voices...
int voicesSoFar = 0;
int voicesNeeded = 300;
var eligibleVoters = voters.TakeWhile((p => (voicesSoFar += p.Voices) < voicesNeeded ));

Answer 1

In a situation where I wanted to execute a function until and including it hit an end condition I did:

public static IEnumerable<T> TakeUntilIncluding<T>(this IEnumerable<T> list, Func<T, bool> predicate)
{
    foreach(T el in list)
    {
        yield return el;
        if (predicate(el))
            yield break;
    }
}

Worked for me! I think this is an implementation-agnostic solution like Jason's, but simpler.

Answer 2

You're looking for

voters.TakeWhile(p => {
   bool exceeded = voicesSoFar > voicesNeeded ;
   voicesSoFar += p.Voices;
   return !exceeded;
});

If you insist on a one-liner, this will work by comparing the previous value:

voters.TakeWhile(p => (voicesSoFar += p.Voices) - p.Voices < voicesNeeded);