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Is it exist some alternative of LINQ Select() method in the Swift language?

As example, in c# I can do the following:

var ranks = cards.Select(a=> a.Rank).ToArray();

but how I can do the same thing using Swift language?

Andrew_STOP_RU_WAR_IN_UA
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  • The `Rank` property of `Card` should be called `rank`, in line with Swift naming conventions. C# uses capitals for properties, and lowercase (or `_` prefix) for instance variables. Swift doesn't have instance variables, so there's no need for the distinction. Properties areLowerCamelCase, and capital camel case is reserved for types and static properties – Alexander Nov 02 '16 at 22:03

1 Answers1

6

map(_:)

let ranks = cards.map{ $0.Rank }

which is syntactic sugar for:

let ranks = cards.map({ (card: Card) -> Rank in
    return card.rank
})

The applied syntactic sugar includes:

  1. Trailing closure syntax

    let ranks = cards.map { (card: Card) -> Rank in
    return card.rank
}

  2. Argument type inference

    let ranks = cards.map { card -> Rank in
    return card.rank
}

  3. Return type inference

    let ranks = cards.map { card in
    return card.rank
}

  4. Implicit return value

    let ranks = cards.map { card in
   card.rank
}

  5. Anonymous closure arguments

    let ranks = cards.map { $0.rank }

Check out the language guide section on closures (the Swift name for what C# calls lambdas) for more information,

Alexander
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  • Looks like this is it! Thanks a lot. – Andrew_STOP_RU_WAR_IN_UA Nov 02 '16 at 21:56
  • @Andrew I gave break down of how the various syntactic sugars are applied to reach the final form I showed. It's covered in the language guide. You should definitely read it, it's very well written, and will be a breeze to understand if you already know C#. – Alexander Nov 02 '16 at 22:06