ios - 字典中的 swift 行动不可预测

Question

我在字典参数中有一组参数:[String: Any]。此外，我有一些此类参数，我的应用程序需要存储它们并在按下按钮时切换每个参数。

代码:

var filterParameters: [String: Any] = [:]
var countryFilterParameters: [String: Any] = [:]

@IBAction func segmentHasChanged(_ sender: Any) {
    if let segment = sender as? UISegmentedControl {
        let currentCountryCode = ApiManager.shared.mainCountryCode
        switch segment.selectedSegmentIndex {
        case 0:
            let filterParametersCopy = self.filterParameters
            self.countryFilterParameters[currentCountryCode] = filterParametersCopy
            ApiManager.shared.setCountryCode(_countryCode: "kz")
            if let uwCountryFilterParameters = self.countryFilterParameters["kz"] as? [String : Any] {
                self.filterParameters = uwCountryFilterParameters
            } else {
                self.filterParameters.removeAll()
            }
            break
        case 1:
            let filterParametersCopy = self.filterParameters
            self.countryFilterParameters[currentCountryCode] = filterParametersCopy
            ApiManager.shared.setCountryCode(_countryCode: "ru")
            if let uwCountryFilterParameters = self.countryFilterParameters["ru"] as? [String : Any] {
                self.filterParameters = uwCountryFilterParameters
            } else {
                self.filterParameters.removeAll()
            }
            break
        case 2:
            let filterParametersCopy = self.filterParameters
            self.countryFilterParameters[currentCountryCode] = filterParametersCopy
            ApiManager.shared.setCountryCode(_countryCode: "by")
            if let uwCountryFilterParameters = self.countryFilterParameters["by"] as? [String : Any] {
                self.filterParameters = uwCountryFilterParameters
            } else {
                self.filterParameters.removeAll()
            }
            break
        default:
            break
        }
        self.loadTenders()
    }
}

预期字典:

["kz": ["q": "some key word", "start_date": ""],
 "ru": ["q": "other key word", "start_date": ""]]

但每次我尝试访问countryFilterParameters时，它都会删除旧值。即:当我执行 CountryFilterParameters["by"] = ["q": "another key word", "start_date": ""] 时。debugPrint(CountryFilterParameters) 打印 ["by": ["q": "另一个关键字", "start_date": ""]]

问题是每次将新键值添加到全局字典时，它都会删除旧键值。可能是什么问题以及如何解决它？

我读到字典是一个结构，所以它是一个值类型。所以我很困惑，哪里做错了？

Answer 1

尝试删除 else 部分，从代码中删除字典的所有值。

        else {
                self.filterParameters.removeAll()
            }

从两个案例中删除此语句。