What does '=>' do in C#?

Question

Possible Duplicates:
Lamda Explanation and what it is as well as a good example
What is the => token called?

I have seen this code:

myContext.SomeEntities.Single(x => x.code == code);

And I don´t know what does the => operator do.

Every search on google about the operator returns no results.

Thank you.

similar: http://stackoverflow.com/questions/5873603/whats-the-point-of-a-lambda-expression — , Jun 21 '11 at 17:16
http://stackoverflow.com/questions/274022/how-do-i-pronounce-as-used-in-lambda-expressions-in-net — Bob G, Jun 21 '11 at 17:17
@Steve: Is that even a duplicate? That user in your question knows what a lambda expression is, @Javiere does not. He is asking what => does much like someone would ask what the ! sign does. — , Jun 21 '11 at 17:17
google can't handle searching for `=>` search for lambda instead. — Nix, Jun 21 '11 at 17:18
@0A0D - I dunno, that q seemed to cover the required ground to me. Syntax and semantics. — Steve Townsend, Jun 21 '11 at 17:32

score 15 · Accepted Answer · edited Jun 20 '20 at 09:12

15

The => operator designates a Lambda Expression:

A lambda expression is an anonymous function that can contain expressions and statements, and can be used to create delegates or expression tree types.

All lambda expressions use the lambda operator =>, which is read as "goes to". The left side of the lambda operator specifies the input parameters (if any) and the right side holds the expression or statement block. The lambda expression x => x * x is read "x goes to x times x." This expression can be assigned to a delegate type as follows:

static void Main(string[] args)
{
    Func<int, int> func = x => x * x;
    int j = func(5);
    // j == 25
}

edited Jun 20 '20 at 09:12

Community

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answered Jun 21 '11 at 17:15

dtb

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I've also seen/heard "maps to" instead of "goes to". – Richard J Foster Jun 21 '11 at 17:17
+1 for taking more time, then the other answers, to copy and paste a quote (even though this has already been covered) and providing an example. – Nix Jun 21 '11 at 17:18
@Richard: Or "for which" – Jun 21 '11 at 17:18

score 2 · Answer 2 · answered Jun 21 '11 at 17:15

2

Lambda expressions, very cool.

http://msdn.microsoft.com/en-us/library/bb397687.aspx

answered Jun 21 '11 at 17:15

Dean Thomas

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score 2 · Answer 3 · edited Jul 31 '19 at 10:25

2

It signals that the code is a lambda expression.

More info: http://msdn.microsoft.com/en-us/library/bb397687.aspx

edited Jul 31 '19 at 10:25

Harry

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answered Jun 21 '11 at 17:15

Jeff

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score 2 · Answer 4 · answered Jun 21 '11 at 17:16

2

This is defining a lambda. You can read it "x goes to x.code equals code," and it means that given x, return the result of the given comparison.

answered Jun 21 '11 at 17:16

David Ruttka

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score 1 · Answer 5 · answered Jun 21 '11 at 17:15

1

They are related to lambda expressions.

You can read about Lambda Expressions here: http://www.rvenables.com/2009/03/practical-introduction-to-lambda-expressions/

answered Jun 21 '11 at 17:15

jessegavin

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What does '=>' do in C#?

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