Is there a shorter/simpler version of the for loop to anything x times?

Question

Usually we do something like a for or while loop with a counter:

for (int i = 0; i < 10; i++)
{
    list.Add(GetRandomItem());
}

but sometimes you mix up with boundaries. You could use a while loop instead, but if you make a mistake this loop is infinite...

In Perl for example I would use the more obvious

for(1..10){
    list->add(getRandomItem());
}

Is there something like "doitXtimes(10){...}"?

Answer 1

Well you can easily write your own extension method:

public static void Times(this int count, Action action)
{
    for (int i = 0; i < count; i++)
    {
        action();
    }
}

Then you can write:

10.Times(() => list.Add(GetRandomItem()));

I'm not sure I'd actually suggest that you do that, but it's an option. I don't believe there's anything like that in the framework, although you can use Enumerable.Range or Enumerable.Repeat to create a lazy sequence of an appropriate length, which can be useful in some situations.

Answer 2

One can create an IEnumerable of Int32:

Enumerable.Range(0, 10);

The ForEach extension method is also widely known (although not shipped with .NET). You could combine the two:

Enumerable.Range(0, 10).ForEach(index => ...);

So your example would become:

Enumerable.Range(0, 10).ForEach(_ => list.Add(GetRandomItem()));

Answer 3

foreach (var i in Enumerable.Range(0, N))
{
    // do something
}

Answer 4

I see Jon Skeet beat me to it, but this variation will allow you to pass the index to the Action each time it is run:

public static class IntegerExtensions
{
   public static void TimesWithIndex(this int count, Action<int> action)
  {
     for (int i = 0; i < count; i++)
        action(i);
  }
}

And call it like this:

10.TimesWithIndex((i) =>
            object[i].DoSomething());