将 Javascript Reduce 函数转换为 C#

Question

我正在尝试将此函数从 Javascript 转换为 C#。目标是接收合同列表并将它们分类为子组，如果它们具有相同的客户，则将它们捆绑在一起。

> let c1 = {id:1,name:"c1"} 
> let c2 = {id:2,name:"c2"} 
> let c3 =  {id:2,name:"c3"} 
> let c4 = {id:1,name:"c4"} 
> let c5 = {id:3,name:"c5"}
> let list = [c1,c2,c3,c4,c5]
> 
> const groupByKey = (array, property) => {   return
> array.reduce((accumulator, object) => {
>     const key = object[property];
> 
>     if (!accumulator[key]) {
>       accumulator[key] = []
>     }
>     accumulator[key].push(object)
>     return accumulator;   }, {}) }
> 
> groupByKey(list, "id") 
> 
> // input = let list = [c1,c2,c3,c4,c5] //output =
> {"1":[{"id":1,"name":"c1"},{"id":1,"name":"c4"}],"2":[{"id":2,"name":"c2"},{"id":2,"name":"c3"}],"3":[{"id":3,"name":"c5"}]}

// 最好输出是包含捆绑合同的列表列表。

更新：我已经编写了函数，问题是我需要 return 只是合同 ID，而不是整个对象。

desired output [[c1.id,c4.id],[c2.id,c3.id],[c5.id]]

这是我目前拥有的。

        public JsonResult checkForSameClient(long[] listOfContracts)
        {
// here i grab the list of contracts ids then go to my repository and find //the whole objects to be compared.






IQueryable<ContratEspace> contrats = contratEspaceRepository.Get(1, listOfContracts.Count(), listOfContracts);
                var contratList = contrats.ToList();

            var finalArray = contrats.GroupBy(c => c.id_clientGestion).ToList();
            return new JsonResult() { Data = finalArray };
        }

但这不是 return 正确 Json.Data 我有错误：

SyntaxError: Unexpected token < in JSON at position 0
    at JSON.parse (<anonymous>)
    at fromJson (angular.js:1282)
    at defaultHttpResponseTransform (angular.js:10133)
    at angular.js:10224
    at forEach (angular.js:321)
    at transformData (angular.js:10223)
    at transformResponse (angular.js:10996)
    at processQueue (angular.js:15552)
    at angular.js:15568
    at Scope.$eval (angular.js:16820)

Answer 1

由于 GroupBy 内置于 .NET 中，因此无需编写聚合函数。

如何在 C# 中对列表进行分组：

var list = new [] {
   new { Id = 1, Name = "c1"},
   new { Id = 2, Name = "c2"},
   new { Id = 2, Name = "c3"},
   new { Id = 1, Name = "c4"},
   new { Id = 3, Name = "c5"},
};

var grouped = list.GroupBy(x => x.Id);

lambda 函数 x => x.Id 可以根据您的需要进行定制

https://docs.microsoft.com/en-us/dotnet/api/system.linq.enumerable.groupby?view=netcore-3.1

将 Javascript Reduce 函数转换为 C#

Convert Javascript Reduce Function to C#

javascript

c#

arrays

entity-framework

jsonresult