Swift 中的元组数组

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2022-01-01 15

Array of tuples in Swift(Swift 中的元组数组)

本文介绍了Swift 中的元组数组的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我有一个函数:

func parseJSON3(inputData: NSData) -> NSArray {
    var tempDict: (id:Int, ccomments:Int, post_date:String, post_title:String, url:String) = (id: 0, ccomments: 0, post_date: "null", post_title: "null", url: "null")
    var resultArray: (id:Int, ccomments:Int, post_date:String, post_title:String, url:String)[] = []
    var error: NSError?
    var jsonDictionary: NSDictionary = NSJSONSerialization.JSONObjectWithData(inputData, options: NSJSONReadingOptions.MutableContainers, error: &error) as NSDictionary
    var firstArray = jsonDictionary.objectForKey("locations") as NSArray
    for dict in firstArray {
        tempDict.id = dict.valueForKey("ID") as Int
        tempDict.ccomments = dict.valueForKey("ccomments") as Int
        tempDict.post_date = dict.valueForKey("post_date") as String
        tempDict.post_title = dict.valueForKey("post_title") as String
        tempDict.url = dict.valueForKey("url") as String
        resultArray.append(tempDict)
    }
    return resultArray
}

排队

resultArray.append(tempDict)

我有一个错误:

调用中的参数ccomments"缺少参数

为什么?请帮忙....

Why? Help please....

推荐答案

在我看来 resultArray.append() 有点像对待可变参数，并试图扩展元组匹配它自己的参数.它抱怨你的第二个参数，因为它只期待一个.我还没有在任何地方看到 Array.append() 的这种行为，所以我会说这是 Swift 中的一个错误.

It looks to me like resultArray.append() is treating the tuple a little bit like a variadic parameter, and trying to expand the tuple to match its own arguments. It's complaining about your second parameter because it's only expecting one. I haven't seen this behavior for Array.append() documented anywhere, so I would say it's a bug in Swift.

使用附加运算符 += 似乎没有这个问题:

Using the appending operator += doesn't seem to have that issue: