Swift enumerate函数

本文主要是介绍Swift enumerate函数，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

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本文的Swift语言版本，1.2

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先看看问题

把这两个数组合成一个字典

score = [1,2,3,4,5,6,7,8,9]
dates =["7/12/15","7/12/15","7/12/15","7/12/15","7/13/15","7/13/15","7/13/15","7/13/15"," 7/14/15"] 

期望的合成后结果

var scoreDatesDictionary = [
"7/12/15": [1,2,3,4]
"7/13/15": [5,6,7,8]
"7/14/15": [9]
] 

我给出的答案：能解决问题，但是不够优雅，不够简洁，因为我对Swift很多global的函数掌握的不是很好，最近开发项目还是用OC。以后遇到了我没掌握好的，就用博客记录下来。

 let  score = [1,2,3,4,5,6,7,8,9,]let  dates = ["7/12/15","7/12/15","7/12/15","7/12/15","7/13/15","7/13/15","7/13/15","7/13/15"," 7/14/15"]var dic = [String:[Int]]()for var index=0;index < dates.count; index++ {let key = dates[index];var value = dic[key]if value == nil{dic[key] = [score[index]]}else{value!.append(score[index])dic[key] = value}}println(dic) 

参考答案

let score = [1,2,3,4,5,6,7,8,9]
let dates = ["7/12/15","7/12/15","7/12/15","7/12/15","7/13/15","7/13/15","7/13/15","7/13/15"," 7/14/15"]
var dic = [String:[Int]]()for (index, date) in enumerate(dates) {dic[date] = (dic[date] ?? []) + [score[index]]
}
print(dic)  // prints "[7/12/15: [1, 2, 3, 4],  7/14/15: [9], 7/13/15: [5, 6, 7, 8]]" 

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enumerate 函数－Swift 1.2

遍历数组和字符串的方式，同时返回index以及数据

 let str = "Wenchen"for (index,character) in enumerate(str){println("\(index):\(character)")} 

输出

0:W
1:e
2:n
3:c
4:h
5:e
6:n 

遍历数组的例子

 let myArray = ["Wen","Chen","Huang"]for (index,str) in enumerate(myArray){println("\(index):\(str)")} 

输出

0:Wen
1:Chen
2:Huang

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