本文的Swift语言版本，1.2

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","7/13/15"," 7/14/15"] 

期望的合成后结果

var scoreDatesDictionary = [
"7/12/15": [1,4]
"7/13/15": [5,8]
"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 = [1,9,]
    let  dates = ["7/12/15"," 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 = [1,9]
let dates = ["7/12/15"," 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]]"

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