Is there a situation where the use of the lambda expression is particularly helpful or its mainly usage is to write less code?
asked Feb 27, 2010 at 15:20
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10Isn't writing more concise and readable code already particularly helpful?Joey– Joey2010-02-27 15:22:45 +00:00Commented Feb 27, 2010 at 15:22
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Take a look at John Skeet's SO answer here. And here is another SO question with specific uses of lambdasDavid Robbins– David Robbins2010-02-27 15:27:12 +00:00Commented Feb 27, 2010 at 15:27
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2Eh eh, sure it is. But I would like to know if it is the only topic... :-)Maurizio Reginelli– Maurizio Reginelli2010-02-27 15:31:47 +00:00Commented Feb 27, 2010 at 15:31
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2 Answers
The justification for adding lambdas to the language was two things.
(1) They make syntactic transformation of query comprehensions possible. When you say
from customer in customers
where customer.City == "London"
select customer
That becomes
customers.Where(customer=>customer.City == "London")
(2) They can be turned into expression trees, and thereby make LINQ-to-SQL, LINQ-to-Entities, and so on, possible. That is, they can represent both the ability to do their semantics and the ability to inspect their structure.
answered Feb 27, 2010 at 15:32
3 Comments
Maurizio Reginelli
Could you provide an example of an expression tree, please? Thanks
David Robbins
@Eric - You forgot to say "And they're just really cool" ;)
Eric Lippert
@Maurizio: blogs.msdn.com/charlie/archive/2008/01/31/…
Lambda expressions are syntactic sugar for anonymous methods, and their use cases are mostly the same.
Lambdas can also be converted to expression trees.
As they are much shorter and easier to write (at least for the simple cases), that in itself is helpful.
2 Comments
Maurizio Reginelli
I like the expression "syntactic sugar", I didn't know it.
Jon Skeet
Not quite the same - lambda expressions can also be converted into expression trees, whereas anonymous methods can't. (There's no such term as "anonymous delegate" - there are anonymous methods, and anonymous functions - that latter is a term covering both anonymous methods an lambda expressions.