如何初始化包含字典列表的字典？ [英] How to initialize a dictionary containing lists of dictionaries?

问题描述

我开始在C＃中进行一些开发，我在这里遇到问题。通常我在Python中开发，这样的东西很容易实现（至少对我来说），但是我不知道如何在C＃中执行此操作：

我想创建一个字典，其中包含以下使用Generic Collections的字典列表：

  {alfred，[{age 20.0}。 {height_cm，180.1}]，
barbara，[{age，18.5}，{height_cm，167.3}]，
chris，[{age }，{height_cm，179.0}] 
} 
  

我从以下开始：

 使用System.Collections.Generic; 
字典< String，Dictionary< String，double> []>者; 
  

但是，我想从上面将三个记录一次性插入到人员中。我一直困扰着语法错误。

任何人都有解决方案吗？

编辑：

谢谢大家 - 我没想到在这么短的时间内会收到很多很好的答案！你很棒！

解决方案

您可以使用字典初始化。不如Python那么优雅，但可以与以下方式一起使用：

  var persons = new Dictionary< string，Dictionary< string，double>> ; 
 {
 {alfred，新词典< string，double> {{age，20.0}，{height_cm，180.1}}}，
 {barbara，新词典< string，double> {{age，18.5}，{height_cm，167.3}}}，
 {chris，新词典< string，double> {{age，39.0}，{height_cm，179.0}}} 
}; 
  

然后：

 人[ 阿尔弗雷德] [ 年龄]; 
  

另请注意，您需要 Dictionary< string，Dictionary< string，double> < / code>，而不是字典< string，Dictionary< string，double> []> 。

同样使用这样的结构可能会有一点PITA，损害可读性和编译时类型的安全性。

在.NET中，喜欢使用强类型的对象，如下所示：

  public class Person 
 {
 public double Age {get;组; } 
 public string Name {get;组; } 
 public double HeightCm {get;组; 
} 
  

然后：

  var persons = new [] 
 {
 new Person {Name =alfred，Age = 20.0，HeightCm = 180.1}，
 new Person {Name =barbara，Age = 18.5，HeightCm = 180.1}，
 new Person {Name =chris，Age = 39.0，HeightCm = 179.0}，
}; 
  

然后您可以使用LINQ获取所需的任何信息：

  double barbarasAge = 
（from p in persons 
其中p.Name ==barbara
 select p.Age） 。第一（）;当然，使用集合不会像哈希表查找一样快，但是取决于你的您可以根据自己的表现来满足需求。
 
I am starting to do a little development in C#, and I am stuck with a problem here. Usually I develop in Python where stuff like this is being implemented easily (at least for me), but I have no idea how to do that in C#:

I want to create a dictionary containing a list of dictionaries like the following using Generic Collections:
{ "alfred",  [ {"age", 20.0}. {"height_cm", 180.1} ],
  "barbara", [ {"age", 18.5}, {"height_cm", 167.3} ],
  "chris",   [ {"age", 39.0}, {"height_cm", 179.0} ]
}
I started with the following:
using System.Collections.Generic;
Dictionary<String, Dictionary<String, double>[]> persons;
But then I'd like to insert the three records from above at once into persons. I am stuck with syntax errors all the way. 

Anyone have a solution for me?

Edit:

Thank you all - I didn't expect to receive so many well thought answers in such a short time! You are great!
解决方案
You could use dictionary initializes. Not as elegant as Python, but could live with:
var persons = new Dictionary<string, Dictionary<string, double>>
{
    { "alfred", new Dictionary<string, double> { { "age", 20.0 }, { "height_cm", 180.1 } } },
    { "barbara", new Dictionary<string, double> { { "age", 18.5 }, { "height_cm", 167.3 } } },
    { "chris", new Dictionary<string, double> { { "age", 39.0 }, { "height_cm", 179.0 } } }
};
And then:
persons["alfred"]["age"];
Also notice that you need Dictionary<string, Dictionary<string, double>> for this structure and not Dictionary<string, Dictionary<string, double>[]>.

Also working with such structure could be a little PITA and harm readability and compile-time type safety of the code.

In .NET it is preferred to work with strongly typed objects, like this:
public class Person
{
    public double Age { get; set; }
    public string Name { get; set; }
    public double HeightCm { get; set; }
}
and then:
var persons = new[]
{
    new Person { Name = "alfred", Age = 20.0, HeightCm = 180.1 },
    new Person { Name = "barbara", Age = 18.5, HeightCm = 180.1 },
    new Person { Name = "chris", Age = 39.0, HeightCm = 179.0 },
};
and then you could use LINQ to fetch whatever information you need:
double barbarasAge = 
    (from p in persons
     where p.Name == "barbara"
     select p.Age).First();
To be noted of course that using collections would not be as fast as a hashtable lookup but depending on your needs in terms of performance you could also live with that.

                        
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