ios - 查找并组合数组中的重复条目

Question

我是新来的，所以如果我的格式不正确，请纠正我(对于 swift 来说也是新的)，但基本上我想做的是获取日期和数字的数组，如果任何日期相同，则将将数字合并到一个条目中。

所以这个

//This is how i format the data after i pull it from core data
var dateAndEntry = [(String, Double)]

//i've split them into two seperate arrays for sorting, but I feel like theres a better way i don't know
var dates = ["01/01/2016", "02/01/2016", "02/01/2016", "04/01/2016", "05/01/2016", "06/01/2016","07/01/2016","07/01/2016"]
var entries = [-14,2,8,9,-1,8,25,6]

变成这样

var dates = ["01/01/2016", "02/01/2016", "04/01/2016", "05/01/2016", "06/01/2016","07/01/2016"]
var entries = [-14,10,9,-1,8,19]

我已经尝试这样做，但我只能得到它，以便它创建一个仅包含新值的新数组，而不是允许我获取重复的值，组合，在索引处插入，然后删除两个中的原始条目数组。

func combineDuplicates(dates: [String]) -> [String]{
    var output: [String] = []
    var checked = Set<String>()
    for date in dates {

        if !checked.contains(date) {
            checked.insert(date)
            output.append(date)
        }
    }
    print(output)
    return output
}

let sorted = combineDuplicates(dates)
print(sorted)

是的，我在谷歌和这里寻找答案，但一无所获。

任何解决方案、解释、帮助、指示或对我可能错过的其他问题或来源的引用都将不胜感激。

Answer 1

这将为您提供一个字典，其中键为日期，值为每个日期的条目总和:

dates.enumerate().reduce([String:Int]()) { dict, item in
    var dict = dict
    dict[item.1] = (dict[item.1] ?? 0) + entries[item.0]
    return dict
}
// ["06/01/2016": 8, "04/01/2016": 9, "01/01/2016": -14, "05/01/2016": -1, "07/01/2016": 31, "02/01/2016": 10]