Lambda expression with a void input

Question

Ok, very silly question.

x => x * 2

is a lambda representing the same thing as a delegate for

int Foo(x) { return x * 2; }

But what is the lambda equivalent of

int Bar() { return 2; }

??

Thanks a lot!

Solution 1

The nullary lambda equivalent would be () => 2.

Solution 2

That would be:

() => 2

Example usage:

var list = new List<int>(Enumerable.Range(0, 10));
Func<int> x = () => 2;
list.ForEach(i => Console.WriteLine(x() * i));

As requested in the comments, here's a breakdown of the above sample...

// initialize a list of integers. Enumerable.Range returns 0-9,
// which is passed to the overloaded List constructor that accepts
// an IEnumerable<T>
var list = new List<int>(Enumerable.Range(0, 10));

// initialize an expression lambda that returns 2
Func<int> x = () => 2;

// using the List.ForEach method, iterate over the integers to write something
// to the console.
// Execute the expression lambda by calling x() (which returns 2)
// and multiply the result by the current integer
list.ForEach(i => Console.WriteLine(x() * i));

// Result: 0,2,4,6,8,10,12,14,16,18

Solution 3

You can just use () if you have no parameters.

() => 2;

Solution 4

The lmabda is:

() => 2

View more solutions

Comments

[Luk]

Damn, that was fast :) Thanks everyone!

[PussInBoots]

Hi, this seems like a great example; can you explain it in plain english line by line, piece by piece? :)

[Ahmad Mageed]

@PussInBoots added some comments. Hope that helps!

[PussInBoots]

Thanks. Still a bit puzzled by Func<int> x and x().. I think I need to read up a little bit more on Func, delegates and lambdas..

[deetz]

Could someone explain to me, what would be the advantage of this in comparison to just using an constant?