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Multiple Where clauses in Lambda expressions

Tags:

c#

.net

lambda

People also ask

Can we use multiple where clause in LINQ?

Well, you can just put multiple "where" clauses in directly, but I don't think you want to. Multiple "where" clauses ends up with a more restrictive filter - I think you want a less restrictive one.

Can lambda expressions contain multiple statements?

In particular, a lambda function has the following characteristics: It can only contain expressions and can't include statements in its body.

What are the two conditions required for using a lambda function in a stream?

In order to match a lambda to a single method interface, also called a "functional interface", several conditions need to be met: The functional interface has to have exactly one unimplemented method, and that method (naturally) has to be abstract.

What is lambda expression in C#?

Lambda expressions in C# are used like anonymous functions, with the difference that in Lambda expressions you don't need to specify the type of the value that you input thus making it more flexible to use. The '=>' is the lambda operator which is used in all lambda expressions.


Can be

x => x.Lists.Include(l => l.Title)
     .Where(l => l.Title != String.Empty && l.InternalName != String.Empty)

or

x => x.Lists.Include(l => l.Title)
     .Where(l => l.Title != String.Empty)
     .Where(l => l.InternalName != String.Empty)

When you are looking at Where implementation, you can see it accepts a Func(T, bool); that means:

  • T is your IEnumerable type
  • bool means it needs to return a boolean value

So, when you do

.Where(l => l.InternalName != String.Empty)
//     ^                   ^---------- boolean part
//     |------------------------------ "T" part

The lambda you pass to Where can include any normal C# code, for example the && operator:

.Where(l => l.Title != string.Empty && l.InternalName != string.Empty)

You can include it in the same where statement with the && operator...

x=> x.Lists.Include(l => l.Title).Where(l=>l.Title != String.Empty 
    && l.InternalName != String.Empty)

You can use any of the comparison operators (think of it like doing an if statement) such as...

List<Int32> nums = new List<int>();

nums.Add(3);
nums.Add(10);
nums.Add(5);

var results = nums.Where(x => x == 3 || x == 10);

...would bring back 3 and 10.


Maybe

x=> x.Lists.Include(l => l.Title)
    .Where(l => l.Title != string.Empty)
    .Where(l => l.InternalName != string.Empty)

?

You can probably also put it in the same where clause:

x=> x.Lists.Include(l => l.Title)
    .Where(l => l.Title != string.Empty && l.InternalName != string.Empty)

x=> x.Lists.Include(l => l.Title).Where(l=>l.Title != String.Empty).Where(l => l.Internal NAme != String.Empty)

or

x=> x.Lists.Include(l => l.Title).Where(l=>l.Title != String.Empty && l.Internal NAme != String.Empty)