hslee develop blog

[swift] Functional, lazy protocol

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Feb 12, 2018

source: https://medium.com/swift-programming/using-lazy-to-delay-computation-8aa4ea236d0a

{% highlight swift %}

/// Avoid creating multiple layers of LazySequence wrapper. /// Anything conforming to LazySequenceProtocol is already lazy. extension LazySequenceProtocol { /// Identical to self. public var lazy: Self { get } }

let array2 = [1, 2, 4, 5, 3, 7] let element = array2.map{ $0 * 2 }[3] //7 times print(element)

let array3 = [1, 2, 4, 5, 3, 7] let element3 = array3.lazy.map{ $0 * 2 }[3] //2 times print(element3)

{% endhighlight %}