如何在字典中分配key =>值对？ [英] How to assign key=>value pairs in a Dictionary?

问题描述

这是我的代码：

string[] inputs = new[] {"1:2","5:90","7:12","1:70","29:60"};

//Declare Dictionary
var results = new Dictionary<int, int>();
//Dictionary<int, int> results = new Dictionary<int, int>();

foreach(string pair in inputs)
{
    string[] split = pair.Split(':');
    int key = int.Parse(split[0]);
    int value = int.Parse(split[1]);

    //Check for duplicate of the current ID being checked
    if (results.ContainsKey(key))
    {
        //If the current ID being checked is already in the Dictionary the Qty will be added
        //Dictionary gets Key=key and the Value=value; A new Key and Value is inserted inside the Dictionary
        results[key] = results[key] + value;
    }
    else
    {
        //if No duplicate is found just add the ID and Qty inside the Dictionary
        results[key] = value;
        //results.Add(key,value);
    }
}

var outputs = new List<string>();
foreach(var kvp in results)
{
    outputs.Add(string.Format("{0}:{1}", kvp.Key, kvp.Value));
}

// Turn this back into an array
string[] final = outputs.ToArray();
foreach(string s in final)
{
    Console.WriteLine(s);
}
Console.ReadKey();

我想知道在字典中分配key => value对是否存在区别。

I want to know if the difference if there is between assigning a key=>value pair in a dictionary.

方法1：

results[key] = value;

方法2：

results.Add(key,value);

在方法1中，未调用功能Add（），而是分配了名为结果的字典通过在method1中声明代码以某种方式设置键-值对，我假设它以某种方式在不调用Add（）的情况下自动在字典中添加了键和值。

In method 1, the function Add() was not called but instead the Dictionary named 'results' assigns somehow sets a Key-Value pair by stating code in method1, I assume that it somehow adds the key and value inside the dictionary automatically without Add() being called.

I之所以这样问，是因为我目前是学生，并且我正在学习C＃。

I'm asking this because I'm currently a student and I'm studying C# right now.

先生/女士，您的回答将对您有所帮助，并且非常感谢。谢谢++

Sir/Ma'am, your answers would be of great help and be very much appreciated. Thank you++

推荐答案

索引器的设置方法 Dictionary< TKey，TValue> （当您执行 results [key] = value; 时调用的那个）看起来像：

The Dictionary<TKey, TValue> indexer's set method (the one that is called when you do results[key] = value;) looks like:

set
{
    this.Insert(key, value, false);
}

添加方法看起来像这样：

public void Add(TKey key, TValue value)
{
    this.Insert(key, value, true);
}

唯一的区别是，如果第三个参数为true，则会抛出一个

The only difference being if the third parameter is true, it'll throw an exception if the key already exists.

侧面说明：反编译器是.NET开发人员的第二好朋友（当然，第一个是调试器）。这个答案来自在ILSpy中打开 mscorlib 。

Side note: A decompiler is the .NET developers second best friend (the first of course being the debugger). This answer came from opening mscorlib in ILSpy.

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