Thoughts on foreach with Enumerable.Range vs traditional for loop

Question

In C# 3.0, I\'m liking this style:

// Write the numbers 1 thru 7
foreach (int index in Enumerable.Range( 1, 7 ))
{
    Console.WriteLine(index);
}

Answer 1

I'd like to have the syntax of some other languages like Python, Haskell, etc.

// Write the numbers 1 thru 7
foreach (int index in [1..7])
{
    Console.WriteLine(index);
}

Fortunatly, we got F# now :)

As for C#, I'll have to stick with the Enumerable.Range method.

Answer 2

This is just for fun. (I'd just use the standard "for (int i = 1; i <= 10; i++)" loop format myself.)

foreach (int i in 1.To(10))
{
    Console.WriteLine(i);    // 1,2,3,4,5,6,7,8,9,10
}

// ...

public static IEnumerable<int> To(this int from, int to)
{
    if (from < to)
    {
        while (from <= to)
        {
            yield return from++;
        }
    }
    else
    {
        while (from >= to)
        {
            yield return from--;
        }
    }
}

You could also add a Step extension method too:

foreach (int i in 5.To(-9).Step(2))
{
    Console.WriteLine(i);    // 5,3,1,-1,-3,-5,-7,-9
}

// ...

public static IEnumerable<T> Step<T>(this IEnumerable<T> source, int step)
{
    if (step == 0)
    {
        throw new ArgumentOutOfRangeException("step", "Param cannot be zero.");
    }

    return source.Where((x, i) => (i % step) == 0);
}

Answer 3

I think Range is useful for working with some range inline:

var squares = Enumerable.Range(1, 7).Select(i => i * i);

You can each over. Requires converting to list but keeps things compact when that's what you want.

Enumerable.Range(1, 7).ToList().ForEach(i => Console.WriteLine(i));

But other than for something like this, I'd use traditional for loop.

Answer 4

It seems like quite a long winded approach to a problem that's already solved. There's a whole state machine behind the Enumerable.Range that isn't really needed.

The traditional format is fundamental to development and familiar to all. I don't really see any advantage to your new style.

Answer 5

I agree that in many (or even most cases) foreach is much more readable than a standard for-loop when simply iterating over a collection. However, your choice of using Enumerable.Range(index, count) isn't a strong example of the value of foreach over for.

For a simple range starting from 1, Enumerable.Range(index, count) looks quite readable. However, if the range starts with a different index, it becomes less readable because you have to properly perform index + count - 1 to determine what the last element will be. For example…

// Write the numbers 2 thru 8
foreach (var index in Enumerable.Range( 2, 7 ))
{
    Console.WriteLine(index);
}

In this case, I much prefer the second example.

// Write the numbers 2 thru 8
for (int index = 2; index <= 8; index++)
{
    Console.WriteLine(index);
}

Answer 6

In my opinion the Enumerable.Range() way is more declarative. New and unfamiliar to people? Certainly. But I think this declarative approach yields the same benefits as most other LINQ-related language features.