c# 将字典值组合成新的键值对

Question

我有一个这样的 c# 字典：

我需要做的是将字典键包含“UPC”的值组合成一个具有组合值的新键，因此它如下所示： {[UPC, 000000000333, 789787878999]}

UPC 可以包含一个或多个值。

我想出了下面的代码，首先从信息字典中删除可能的重复项

//Remove any duplicates
        List<string> vals = new List<string>();
        Dictionary<string, string> newDict = new Dictionary<string, string>();
        foreach (KeyValuePair<string, string> item in information)
        {
            if (!vals.Contains(item.Value))
            {
                newDict.Add(item.Key, item.Value);
                vals.Add(item.Value);
            }
        }

        StringBuilder sbUPC = new StringBuilder();
        
        var newDictJustUPCs = newDict.Where(kvp => kvp.Key.Contains("UPC"));

newDictJustUPCs 返回以下内容：

那么我将如何遍历这些 KeyValuePairs 并为具有键“UPC”的 newDict 和组合的两个值创建 KeyValue 对并将其分配给 newDict？

我知道最终答案的一部分将是 newDict.Add("UPC", CombinedUPCValues);

Answer 1

您可以通过多种方式做到这一点。这里只有一个

给定

var dict = new Dictionary<string, string>
{
   { "asd", "dfgdfg" },
   { "ghj", "ghj" },
   { "UPC1", "123" },
   { "UPC2", "345" },
   { "UPC3", "567" }
};

用法

var upc = dict
   .Where(x => x.Key.StartsWith("UPC"))
   .Select(x => x.Value);

var newDict = dict
   .Where(x => !x.Key.StartsWith("UPC"))
   .ToDictionary(x => x.Key, x => x.Value);

newDict.Add("UPC", string.Join(",", upc));


foreach (var item in newDict)
    Console.WriteLine(item.Key + " : "+ item.Value);

输出

asd : dfgdfg
ghj : ghj
UPC : 123,345,567

Answer 2

首先提取所有 UPC 元素并根据需要创建其值，然后将其附加到没有 UPC 元素的新数组中

            var dict = new Dictionary<string, string>
        {
            {"Modified by", "Stuart gill" },
            {"Modified on", "11/2/2021" },
            {"UPC0", "000000000333" },
            {"UPC2", "789789789" },
        };

       var keyValueWithUpc = dict.Where(kv => kv.Key.StartsWith("UPC")).ToArray();
       var upcValue = string.Join(",", keyValueWithUpc.Select(kv => kv.Value));
       var result = dict.Except(keyValueWithUpc)
                         .Append(new KeyValuePair<string, string>("UPC", upcValue))
                         .ToDictionary(x => x.Key, x => x.Value);

Append 方法：它需要源（附加的集合）一个数组而不是一个数组，只是为了与现有的一个进行区分，但是由于它作为一个参数，你也可以传递单个项目

public static class ExtensionMethods
{
    public static IEnumerable<T> Append<T>(this IEnumerable<T> source, params T[] itemsToAppend)
    {
        return source.Concat(itemsToAppend);
    }
}

Answer 3

TheGeneral 用他的代码示例为我指明了正确的方向。这是我的解决方案。传入以下日志信息。

StringBuilder sb = new StringBuilder();
        Dictionary<string, string> information = new Dictionary<string, string>();
        List<string> changes = log.Changes.ToString().Split('?').ToList();
        changes.RemoveAt(changes.Count - 1);
        
        int start = 0;
        
        foreach (string units in changes)
        {
            string[] unit = units.Split('|');
            string[] parts = unit[0].Split('-');
            string[] values = unit[1].Split('^');

            string field = parts[1];
            string orig = values[0];
            
            if (unit[0] == "VendorPartUpc-UPC")
            {
                information.Add(field+start, values[1]);
                start = start + 1;
            }
            else if (values.Count() > 1 && (orig != string.Empty || values[1] != string.Empty) && !information.ContainsKey(field))
                information.Add(field, values[1]);
        }

        //Remove any duplicates
        List<string> vals = new List<string>();
        Dictionary<string, string> newDict = new Dictionary<string, string>();
        foreach (KeyValuePair<string, string> item in information)
        {
            if (!vals.Contains(item.Value))
            {
                newDict.Add(item.Key, item.Value);
                vals.Add(item.Value);
            }
        }
        
        //Need to take the UPCs from multiple key/value pairs, extract just the UPC value and put into a single value with UPC as the key.
        var newDictJustUPCs = newDict.Where(kvp => kvp.Key.Contains("UPC"));
        var upc = newDictJustUPCs
            .Where(x => x.Key.StartsWith("UPC"))
            .Select(x => x.Value);

        newDict.Add("UPC", string.Join(",", upc));
         
        information = newDict;

        return information;