Swift - Storing Collections of Data Using Array(sort(in 0lace, mutable), concatenate(+), Array extension(slicing))

The Swift Programming Language
Apple Inc.

開発環境

• OS X Mavericks - Apple(OS)
• Xcode 6.0 Beta
• Swift (プログラミング言語)

Practical Programming: An Introduction to Computer Science Using Python 3 (Pragmatic Programmers) (Paul Gries (著)、Jennifer Campbell (著)、Jason Montojo (著)、Lynn Beighley (編集)、Pragmatic Bookshelf)のChapter 8(Storing Collections of Data Using Array)、8.9(Exercises) 6-a, b, c, d.をSwiftで考えてみる。

8.9(Exercises) 6-a, b, c, d.

コード(Xcode)

main.swift

//
//  main.swift
//  sample6
//
//  Created by kamimura on 8/25/14.
//  Copyright (c) 2014 kamimura. All rights reserved.
//

import Foundation

println("a.")
var temps:[Double] = [25.2, 16.8, 31.4, 23.9, 28, 22.5, 19.6]
println(temps)

println("b.")
temps.sort({(a:Double, b:Double) in a < b})
println(temps)

println("c.")
let cool_temps = temps.slice(end: 2)
let warm_temps = temps.slice(start: 2)
println(cool_temps)
println(warm_temps)

println("d.")
let temps_in_celsius = cool_temps + warm_temps
println(temps_in_celsius)

array.swift

//
//  array.swift
//  array
//
//  Created by kamimura on 8/21/14.
//  Copyright (c) 2014 kamimura. All rights reserved.
//

import Foundation

extension Array {
    func indexAt(i:Int) -> T {
        if i >= 0 {
            return self[i]
        }
        let new_index:Int = self.count + i
        return self[new_index]
    }
    func slice(start:Int = 0, end:Int? = nil) -> Array {
        var new_start = start >= 0 ? start : self.count + start
        var new_end:Int
        if end == nil {
            new_end = self.count
        } else if end! >= 0 {
            new_end = end!
        } else {
            new_end = self.count + end!
        }
        var result:Array = []
        if new_start >= new_end {
            return []
        }
        for i in new_start..<new_end {
            result.append(self[i])
        }
        return result
    }
}

入出力結果(Console Output)

a.
[25.2, 16.8, 31.4, 23.9, 28.0, 22.5, 19.6]
b.
[16.8, 19.6, 22.5, 23.9, 25.2, 28.0, 31.4]
c.
[16.8, 19.6]
[22.5, 23.9, 25.2, 28.0, 31.4]
d.
[16.8, 19.6, 22.5, 23.9, 25.2, 28.0, 31.4]
Program ended with exit code: 0