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Start your free trialJon Andreas Grenness
5,055 PointsStruggeling to understand LINQ query to find birds
I can't wrap my head around how LINQ queries are meant to be formulated if I have to compare the results in to different lists even when re-watching video multiple times. Some help would be greatly appreciated.
Thank you in advance!
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(yourBird, b => b.Name, n => b.Name, (myBird, myBird.Name) => myBirds);
2 Answers
Steven Parker
231,198 PointsYou're pretty close, you just need a little "fine tuning":
- the first Join argument should be the name of the 2nd iterable "yourBirds" (plural, instead of "yourBird")
- the inner key selector (third argument) should be
n => n.Name
(with "n" instead of "b") - the 2nd parameter of the result selector isn't used, but its name should not have a membership operator (".")
That 2nd lambda parameter can be anything, but I often like to use "_" (underscore) as the name of a parameter that won't be used. The name "unused" is also good.
Jon Andreas Grenness
5,055 PointsI changed the errors you pointed out, and renamed the (myBird, myBird.Name) => myBird to
var ourBirds = myBirds.Join(yourBirds, b => b.Name, n => n.Name, (bird, name) => bird);
and that worked.
Thanks!