ios - 使用唯一键快速合并字典

Question

我正在尝试对具有唯一类型的字典求和-

   let dict1: [String:Any] = ["type":"steps","value": 100]
   let dict2: [String:Any] = ["type":"cal","value": 200]
   let dict3: [String:Any] = ["type":"cal","value": 300]
   let dict4 : [String:Any] = ["type":"steps","value": 400]
   let dict5 : [String:Any] = ["type":"cal","value": 500]

我只是在寻找结果 -

sum is - [["type":"steps","value": 500],["type":"cal","value": 1000]]

我经历了https://developer.apple.com/documentation/swift/dictionary 但没有找到我需要的东西

请帮忙解决这个问题

Answer 1

你可以这样做:

        let dict1: [String:Any] = ["type":"steps","value": 100]
        let dict2: [String:Any] = ["type":"cal","value": 200]
        let dict3: [String:Any] = ["type":"cal","value": 300]
        let dict4 : [String:Any] = ["type":"steps","value": 400]
        let dict5 : [String:Any] = ["type":"cal","value": 500]

        let array = [dict1,dict2,dict3,dict4,dict5]

        let list :[String:[[String:Any]]] = Dictionary(grouping: array, by: {$0["type"] as? String ?? ""})

        let result =  list.map { (key,value) -> [String:Any] in
            let sum = value.reduce(0, {$0 + ($1["value"] as? Int ?? 0)})
            return ["type":key , "value":sum]
        }

        print(result)

输出:

[["type": "cal", "value": 1000], ["type": "steps", "value": 500]]