what is happening in the where method when use over the list?

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5.00/5 (2 votes)

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I have a list of string objects like List<string> myList =new List<string>(); and it contains "Rob", "Look", "Joe" and so on. I use Where method over the myList object using the condition where the length of the each item is not greater than 3 and return those.

My question is what happened when use the where method over the list object.

Hope the question is no so naive. Thanks anyway,

Posted 18-May-12 5:13am

Look87

Updated 18-May-12 5:27am

Shmuel Zang

v2

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3 solutions

Solution 3

Shmuel Zang provided a good reference, but the reference article did not explain how extension methods work, and this is the key:
How does it work in C#? - Part 3 (C# Linq in detail)[^].

Please read this:
http://msdn.microsoft.com/en-us/library/bb383977.aspx[^].

—SA

Posted 18-May-12 6:17am

Sergey Alexandrovich Kryukov

Comments

VJ Reddy 21-May-12 13:03pm

Good references. 5!

Sergey Alexandrovich Kryukov 21-May-12 14:08pm

Thank you, VJ.
--SA

Solution 2

What happens in this case is that each object in the list is passed to predicate supplied in .Where() method. If predicate evaluates to 'true' object is added to result list, and finally that list is returned to your code.

Posted 18-May-12 5:34am

sjelen

Comments

Sergey Alexandrovich Kryukov 18-May-12 12:10pm

OK, and where is "Where"? There is no such thing in the System.Collections.Generic.List<> class... do you know?
--SA

sjelen 21-May-12 10:54am

It's an extension method, member of System.Linq.Enumerable, located in System.Core (at least in .NET 4.0, not sure about previous versions).
Sorry for late reply, I see now it's already mentioned.

Sergey Alexandrovich Kryukov 28-May-12 18:28pm

That's correct, and that was my point -- the use of extension methods; that's why I added my answer to complement the one by Shmuel Zang; please see both...
--SA

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Shmuel Zang · Accepted Answer · 2012-05-18T05:25:00

Solution 1

Try this cp article:

How does it work in C#? - Part 3 (C# Linq in detail)[^]

Posted 18-May-12 5:25am

Shmuel Zang

Comments

Look87 18-May-12 11:59am

Thank you for the ref.

Sergey Alexandrovich Kryukov 18-May-12 12:17pm

That's a good reference, but I notices that extension methods are not explained in this article. I voted 4.
I added my answer with additional link, please see.
--SA

aidin Tajadod 18-May-12 12:30pm

my 5.

Shmuel Zang 19-May-12 16:12pm

Thanks.