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31 lines
1.1 KiB
Swift
31 lines
1.1 KiB
Swift
/*
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Copyright (C) 2015 Apple Inc. All Rights Reserved.
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See LICENSE.txt for this sample’s licensing information
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Abstract:
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A convenient extension to Swift.Dictionary.
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*/
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extension Dictionary {
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/**
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It's not uncommon to want to turn a sequence of values into a dictionary,
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where each value is keyed by some unique identifier. This initializer will
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do that.
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- parameter sequence: The sequence to be iterated
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- parameter keyer: The closure that will be executed for each element in
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the `sequence`. The return value of this closure, if there is one, will
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be used as the key for the value in the `Dictionary`. If the closure
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returns `nil`, then the value will be omitted from the `Dictionary`.
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*/
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init<Sequence: SequenceType where Sequence.Generator.Element == Value>(sequence: Sequence, @noescape keyMapper: Value -> Key?) {
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self.init()
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for item in sequence {
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if let key = keyMapper(item) {
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self[key] = item
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}
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}
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}
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}
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