概述
两个数组组合成一个字典
//数组
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"]
//字典
var scoreDatesDictionary = [
"7/12/15": [1,2,3,4]
"7/13/15": [5,6,7,8]
"7/14/15": [9]
]
解决方案
func enumFunc() {
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 dates.enumerated() {
dic[date] = (dic[date] ?? []) + [score[index]]
}
print("dic = \(dic)")
}
备注：??操作符
a ?? b可以理解成
if a != nil {
return a
} else {
return b
}
//或者
a != nil ? a! : b
