比较后将结果添加到列表中 [英] Add results to a list after compare

问题描述

我有一个文本文件，用于将其客户ID与数据库中的客户ID和状态字典进行比较。在进行比较后，我需要将每个具有客户ID的状态编译为List String，以便我可以再次使用它来检查数据库中的其他详细信息。如果有人有一个例子我可以使用吗？



我尝试过：

 if（！mapping.ContainsKey（ssn））
 {
 newfile + = line + Environment.NewLine; 
 
} 
 else 
 {
 
 List< String> x = mapping.Where（w => w.Value.Contains（TX））
 .Select（n => n.Value）.ToList（）; 
 
} 

mapping是我字典的名称，但到目前为止这似乎不起作用。我需要将比较结果添加到列表中。

解决方案

成为智能开发人员并查看文档：Dictionary(TKey,TValue).ContainsKey Method（TKey）（System.Collections.Generic） [ ^ ]

这是一个基于你的评论和原始问题的例子

 Dictionary< string，int> mapping = 
  new  Dictionary< string，int>（）; 
 
 mapping.Add（  cat， 2 ）; 
 mapping.Add（  dog， 1 ）; 
 mapping.Add（  llama， 0 ）; 
 mapping.Add（  iguana， -  1）; 
 
 List< String> x = mapping.Where（w = >  w.Key.Contains（  a））
。选择（n = >  n.Key）。ToList（）; 

I have a text file that compares its customer ID with a dictionary of Customer ID and State from the database. After it does the compare I need to compile every state with its Customer ID into a List String so I can use that again to check additional details in my database. If someone has an example I can use?

What I have tried:

if (!mapping.ContainsKey(ssn))
                    {
                        newfile += line + Environment.NewLine;
                        
                    }
                    else
                    {

                        List<String> x = mapping.Where(w => w.Value.Contains("TX"))
                            .Select(n => n.Value).ToList();

                    }      

mapping is the name of my dictionary, but so far this doesn't seem to work. I need to add the results of the compare to a list.

解决方案

Be a smart developer and check the documentation: Dictionary(TKey, TValue).ContainsKey Method (TKey) (System.Collections.Generic)[^]

Here is an example based on your comment and original question

Dictionary<string, int> mapping =
new Dictionary<string, int>();

mapping.Add("cat", 2);
mapping.Add("dog", 1);
mapping.Add("llama", 0);
mapping.Add("iguana", -1);

List<String> x = mapping.Where(w=> w.Key.Contains("a"))
   .Select(n => n.Key).ToList();

这篇关于比较后将结果添加到列表中的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！