LINQ, simplifying expression - take while sum of taken does not exceed given value

Question

Given a setup like this ..

class Product {
   int Cost;
   // other properties unimportant
}

var products = new List {
    new Product { Cost         


        

Answer 1

ok, re my comment above in @Aducci's answer, here's a version using Scan

      var result=products.Scan(new {Product=(Product)null, RunningSum=0},
        (self, next) => new {Product=next, RunningSum=self.RunningSum+next.Cost})
        .Where(x=>x.RunningSum<=credit)
        .Select(x => x.Product);

And this is my implementation of Scan (which I assume is similar to what's in the Rx Framework, but I haven't checked)

    public static IEnumerable Scan(this IEnumerable source,
      TAccumulate seed, Func accumulator) {

      foreach(var item in source) {
        seed=accumulator(seed, item);
        yield return seed;
      }
    }