在 C# 中的另一个列表中搜索列表中的项目

Question

我想将列表中的任何字符串项与另一个列表中的子字符串项进行匹配，然后将子字符串和重复放入字典中而不使用 for 循环，因为子字符串列表包含 24345000 个单元格。

 string[] folders = Directory.GetDirectories(@"..\Raw Data", "*");
 Dictionary<string, int> freq = new Dictionary<string, int>();
 var letters= File.ReadAllLines(@"..\letters.txt").ToList();
 foreach (string folder in folders)
        {
            string name_folder = Path.GetFileName(folder);

            string[] N_F = Directory.GetFiles(@"..\items\" + folder, "*.txt");
            foreach (string f in N_F)
            {
                List<string> s = File.ReadAllText(f).Split(' ').ToList();
                s.RemoveAll(string.IsNullOrWhiteSpace);
                foreach(string t in letters)
                    if(s.Contains(t))
                if (freq.ContainsKey(t))
                        freq[t]++;
                    else
                        freq[t] = 1;
            }
}

Answer 1

您正在寻找一种方法来搜索另一个列表中的列表中的单词出现次数。

// Sample Data 
var letters = new string[] { "Apple", "Orange", "Mango", "Cherry" };
var masterList = new string[] 
                { "Apple", "Tea", "Mango", "Apple", "Wheat", "Mango",
                  "Bread", "Orange", "Mango", "Apple", "Orange", "Mango",
                  "Apple", "Bread", "Mango", "Apple", "Bread", "Tea"
                }; 

你可以试试：

var freq = words.Select(w => new { Word = w, Count = masterList.Count(m => m == w) })
                              .ToList();

freq将包含：

Word = Apple    Count = 5
Word = Orange    Count = 2
Word = Mango    Count = 5
Word = Cherry    Count = 0