说我有斯威夫特字典混乱
var dict = parseJSON(getJSON(url)) // This results in an NSDictionary
为什么
let a = dict["list"]![1]! as NSDictionary
let b = a["temp"]!["min"]! as Float
允许的,而这个:
let b = dict["list"]![1]!["temp"]!["min"]! as Float
导致错误:
Type 'String' does not conform to protocol 'NSCopying'
请解释为什么会发生这种情况,请注意我是Swift新手,没有任何经验。