//: Playground - noun: a place where people can play

 import UIKit

 var str = "Hello, playground"

 /// 使用map函数，进行数组内部数据的转换，map中接受一个转换函数

 var array =  [,,,,]

 var newArray = array.map({$ * })

 print(newArray)

  /// 使用reduce 函数 求和

 var sum = array.reduce(, combine: +)

 print(sum)

 /// 使用 filter来验证tweet中是否包含选定的若干关键字中的一个

 let words = ["Swift","iOS","cocoa","OSX","tvOS"]

 let tweet = "This is an example tweet larking about Swift"

 let valid = !words.filter({tweet.containsString($)}).isEmpty

 print(valid)

 let valid1 = words.contains(tweet.containsString)

 print(valid1)

 let valid2 = tweet.characters.split(" ").lazy.map(String.init).contains(Set(words).contains)

 print(valid2)

  /// 使用split map 分隔内容

 let text = "窗前明月光 疑是地上霜 举头望明月 低头思故乡"

 let lines = text.characters.split(" ").map(String.init)

 print(lines[])

 print(lines[])

 print(lines[])

 print(lines[])

 /// 使用forEach 高阶函数便利

 let name = "urai"

 (...).forEach({print("Happy Birthday " + (($ == ) ? "dear \(name)":"to You"))})

 (...).forEach{print("Happy Birthday " + (($ == ) ? "dear \(name)":"to You"))}

 // MARK: - 查找数组中符合条件的数据

 extension SequenceType {

     typealias Element = Self.Generator.Element

     func partitionBy(fu: (Element) -> Bool) -> ([Element],[Element]) {

         var first = [Element]()

         var second = [Element]()

         for el in self {

             if fu(el) {

                 first.append(el)

             }

             else {

                 second.append(el)

             }

         }

         return (first,second)

     }

 }

 let part = [, , , , , ].partitionBy{$ < }

 print(part)

 // MARK: - 一种更简介的查找方式

 extension SequenceType {

     func anotherpartitionBy(fu: (Self.Generator.Element) -> Bool) -> ([Self.Generator.Element],[Self.Generator.Element]) {

         return (self.filter(fu),self.filter({!fu($)}))

     }

 }

 let part1 = [, , , , , ].anotherpartitionBy{$ < }

 print(part1)

 /// 使用的是分区元组，但效率不如上边的高

 var part2 = [, , , , , ].reduce( ([],[]), combine: {

     (a:([Int],[Int]),n:Int) -> ([Int],[Int]) in

     (n<) ? (a.+[n],a.) : (a.,a.+[n])

 })

 print(part2)