CODEWITHSUNDEEP
c#lambdageneric-list
Oneway
Oneway

Reputation: 41

C# List<T> lambda Find then Modify elements

How would I go about doing this with a List using lambda

List<Foo> list....// create and add a bunch of Foo
int seconds = 100;

list.FindAll(x=>(x.Seconds == 0).Seconds = seconds) // yes I know that wont work...

In other words, find all of the foo objects that Seconds == 0 and change the value to my local variable...

I don't want to loop the list...I am sure there is a way to do this with a simple lambda method...

Any help appreciated

Oneway

Upvotes: 2

Views: 15962

Answers (2)

Larry OHeron
Larry OHeron

Reputation: 11

list.FindAll(x => x.Seconds == 0)
    .ForEach(x => x.Seconds = seconds);

I believe that the above does not compile.
.ForEach(...) returns void which can not be on the right-hand side of the FindAll() method.

Upvotes: 1

Jon Skeet
Jon Skeet

Reputation: 1500035

Well, you could do:

list.FindAll(x => x.Seconds == 0)
    .ForEach(x => x.Seconds = seconds);

Personally I'd prefer an explicit loop for the side-effecting part though:

foreach (var x in list.Where(x => x.Seconds == 0))
{
    x.Seconds = seconds;
}

(I'm assuming this is a reference type, by the way. If it's a value type there are all kinds of other reasons why it wouldn't work.)

EDIT: You may wish to have a look at Eric Lippert's thoughts on the matter too.

Upvotes: 11

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