ScanBack

Applies a function to each element of the collection, threading an accumulator argument through the computation.

Take the third argument, and apply the function to it and the last element of the collection. Then feed this result into the function along with the previous element and so on.

Returns the collection of intermediate results and the final result.

This method is similar to FoldBack, but in this case the intermediate results are returned as well.

Parameters	Returns
Func<T, TState, TState> folder IEnumerable<T> source TState state	TState

Usage

Accumulating an individual property of each element through a collection

//IEnumerable<Animal> source = 
//    { ("Cats",4), ("Dogs",5), ("Mice",3), ("Elephants",2) }

int result = source.FoldBack( (_state, element) => _state + element.Item2, 6);

//result = {20, 16, 11, 8}

When the type of elements in your collection are: int, decimal, double, string or bool you can also use this function combined with the Operations described in operations section as folder functions.

Using an operation as a folder

//IEnumerable<int> source = { 0,1, 2, 3, 4, 5, 6, 7, 8, 9, 10 }
int result = source.FoldBack(IntegerOperations.Add, 15);

//result = {65, 65, 64, 62, 59, 55, 50, 44, 37, 29, 20}