zoukankan      html  css  js  c++  java
  • C# Dictionary通过value获取对应的key值

    1:最直白的循环遍历方法,可以分为遍历key--value键值对以及所有的key两种表现形式

    2:用Linq的方式去查询(当然了这里要添加对应的命名空间 using System.Linq)

     如下为一个十分简单的代码示例:

      private void GetDicKeyByValue()
            {
                Dictionary<string, string> dic = new Dictionary<string, string>();
                dic.Add("1", "1");
                dic.Add("2", "2");
                dic.Add("3", "2");
                //foreach KeyValuePair traversing
                foreach (KeyValuePair<string, string> kvp in dic)
                {
                    if (kvp.Value.Equals("2"))
                    {
                        //...... kvp.Key;
                    }
                }

                //foreach dic.Keys
                foreach (string key in dic.Keys)
                {
                    if (dic[key].Equals("2"))
                    {
                        //...... key
                    }
                }

                //Linq
                var keys = dic.Where(q => q.Value == "2").Select(q => q.Key);  //get all keys

                List<string> keyList = (from q in dic
                                        where q.Value == "2"
                                        select q.Key).ToList<string>(); //get all keys

                var firstKey = dic.FirstOrDefault(q => q.Value == "2").Key;  //get first key
            }

  • 相关阅读:
    Python笔记_函数,模块,包的关系
    「GXOI / GZOI2019」宝牌一大堆
    「BalticOI 2020」村庄 (贪心)
    CF Round #635 Div.1 Chiori and Doll Picking (hard version)
    「BalticOI 2020」病毒
    「BalticOI 2020」小丑
    「BalticOI 2020」混合物
    k短路
    「JSOI2019」神经网络
    「NOI2020」时代的眼泪
  • 原文地址:https://www.cnblogs.com/lchsirblog/p/7243021.html
Copyright © 2011-2022 走看看