/// <summary>Applies a key-generating function to each element of a CloudFlow and return a CloudFlow yielding unique keys and the result of the threading an accumulator.</summary>
/// <param name="projection">A function to transform items from the input CloudFlow to keys.</param>
/// <param name="folder">A function that updates the state with each element from the CloudFlow.</param>
/// <param name="combiner">A function that combines partial states into a new state.</param>
/// <param name="state">A function that produces the initial state.</param>
/// <param name="stream">The input CloudFlow.</param>
/// <returns>The final result.</returns>
public static CloudFlow <Tuple <TKey, TAccumulate> > AggregateBy <TSource, TKey, TAccumulate>(this CloudFlow <TSource> stream, Func <TSource, TKey> projection, Func <TAccumulate> state, Func <TAccumulate, TSource, TAccumulate> folder, Func <TAccumulate, TAccumulate, TAccumulate> combiner)
{
return(CSharpProxy.AggregateBy(stream, projection, state, folder, combiner));
}
/// <summary>Applies a state-updating function to a stream of inputs, grouped by key projection.</summary>
/// <param name="projection">A function to transform items of the input stream into comparable keys.</param>
/// <param name="folder">Folding function.</param>
/// <param name="init">State initializing function.</param>
/// <param name="source">The input stream.</param>
/// <returns>A stream of tuples where each tuple contains the unique key and a sequence of all the elements that match the key.</returns>
public static Stream<Tuple<TKey, TState>> AggregateBy<TSource, TKey, TState>(this Stream<TSource> source, Func<TSource,TKey> projection, Func<TState, TSource, TState> folder, Func<TState> init)
{
return CSharpProxy.AggregateBy(source, projection, folder, init);
}
/// <summary>Applies a key-generating function to each element of a ParStream and return a ParStream yielding unique keys and the result of the threading an accumulator.</summary>
/// <param name="projection">A function to transform items from the input ParStream to keys.</param>
/// <param name="folder">A function that updates the state with each element from the ParStream.</param>
/// <param name="state">A function that produces the initial state.</param>
/// <param name="stream">The input ParStream.</param>
/// <returns>The final result.</returns>
public static ParStream <Tuple <TKey, TState> > AggregateBy <TSource, TKey, TState>(this ParStream <TSource> stream, Func <TSource, TKey> projection, Func <TState, TSource, TState> folder, Func <TState> state)
{
return(CSharpProxy.AggregateBy(stream, projection, folder, state));
}