Accumulation of subsequences of a sequence using C#/Linq

Question

I\'m trying to find a better way of processing a sequence of numbers based on the following requirement: the value of sequence[i] is the sum of its own value pl

Answer 1

I built a general purpose (with lots of variations) extension method based on the APL scan operator (analogous to how Aggregate is essentially the APL reduce operator) that returns the intermediate results of the sequence of operations:

public static IEnumerable Scan(this IEnumerable src, TResult seed, Func combine) {
    foreach (var s in src) {
        seed = combine(seed, s);
        yield return seed;
    }
}

Which can then be used like:

var ans = list.Scan(0.0, (a, d) => a+d).ToList();