Generic Map/Reduce List Extensions in C#

According to this link Functional Programming in C# 3.0: How Map/Reduce/Filter can Rock your World the following are the equivalent in C# under the System.Linq namespace:

• map --> Enumerable.Select
• reduce --> Enumerable.Aggregate
• filter --> Enumerable.Where

These look very similar to extensions in Linq already:

//takes a function that matches the Func<T,R> delegate
listInstance.Aggregate( 
    startingValue, 
    (x, y) => /* aggregate two subsequent values */ );

//takes a function that matches the Action<T> delegate
listInstance.ForEach( 
    x => /* do something with x */);

Why is the 2nd example called Transform? Do you intend to change the values in the list somehow? If that's the case you may be better off using ConvertAll<T> or Select<T>.

I would use the built in Func delegates instead. This same code would work on any IEnumerable. Your code would turn into:

public static R Reduce<T,R>(this IEnumerable<T> list, Func<T,R> r, R initial)
{
     var aggregate = initial;
     foreach(var t in list)
         aggregate = r(t,aggregate);

     return aggregate;
}
public static void Transform<T>(this IEnumerable<T> list, Func<T> f)
{
    foreach(var t in list)
             f(t);
}