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C# Querying With LINQ Query Operators Joins

Nathan Reinauer
Nathan Reinauer
2,097 Points

Unexpected symbol ',', expecting ')'

I'm probably missing something stupid, but I can't see it. Where do I have a comma that's supposed to be a closing parenthesis?

CodeChallenge.cs
var myBirds = new List<Bird> 
{ 
    new Bird { Name = "Cardinal", Color = "Red", Sightings = 3 },
    new Bird { Name =  "Dove", Color = "White", Sightings = 2 },
    new Bird { Name =  "Robin", Color = "Red", Sightings = 5 }
};

var yourBirds = new List<Bird> 
{ 
    new Bird { Name =  "Dove", Color = "White", Sightings = 2 },
    new Bird { Name =  "Robin", Color = "Red", Sightings = 5 },
    new Bird { Name =  "Canary", Color = "Yellow", Sightings = 0 }
};

var ourBirds = myBirds.Join(yourBirds,
                            mb => mb.Name,
                            yb => yb.Name,
                            (myBird, yourBird));

1 Answer

Steven Parker
Steven Parker
231,198 Points

:point_right: The fourth argument to Join needs to be a function.

Specifically, it needs to be a function to create a result element from two matching elements It should have this signature: Func<TOuter, TInner, TResult>.

Since you're just returning the objects in common, you can write a lambda expression that takes two arguments and returns either one of them:

(myBird, yourBird) => myBird

It kind of looks like you started to do this but just didn't finish.