计数出现在阵 [英] Counting occurrences in Array

问题描述

我指望阵列中的每个元素的发生，但我得到的错误值不能为空这是没有意义的，我因为ARR1是完全没有空值填充除了最后5个元素这是空。

I am counting the occurrence of each element in the array but I get the error "Value cannot be null" This doesn't make sense to me because arr1 is fully populated with no null values except the last 5 elements which are null.

下面是我的代码。我使用字典的第一次，所以我可能有一些逻辑错误的地方。我正在读从文本文件

Here is my code. I am using dictionary for the first time so I may have some logic error somewhere. I am reading from a textfile.

       string[] arr1 = new string[200];




        StreamReader sr = new StreamReader("newWorkSheet.txt");


                string Templine1 = "";
                int counter = 0;

                while (Templine1 != null)
                {

                    Templine1 = sr.ReadLine();
                   arr1[counter] = Templine1;

                    counter += 1;
                }

                sr.Close();


                // Dictionary, key is number from the list and the associated value is the number of times the key is found
                Dictionary<string, int> occurrences = new Dictionary<string, int>();
                // Loop test data
                foreach (string value in arr1)
                {
                    if (occurrences.ContainsKey(value)) // Check if we have found this key before
                    {
                        // Key exists. Add number of occurrences for this key by one
                        occurrences[value]++;
                    }
                    else
                    {
                        // This is a new key so add it. Number 1 indicates that this key has been found one time
                        occurrences.Add(value, 1);
                    }
                }
                // Dump result

     System.IO.StreamWriter sr2 = new System.IO.StreamWriter("OrganizedVersion.txt");



                foreach (string key in occurrences.Keys)
                {
                    sr2.WriteLine("Integer " + key.ToString() + " was found " + occurrences[key].ToString() + " times");
                }

sr2.Close();


    Console.ReadLine();

编辑：我把这里所有的代码，包括声明。

I put all the code here including declaration.

推荐答案

这不正是你的问题，但LINQ的可以减少这里的行数：

It's not exactly your question but Linq could reduce the number of lines here:

var groups = arr1.GroupBy(item => item);
foreach (var group in groups)
{
  Console.WriteLine(string.Format("{0} occurences of {1}", group.Count(), group.Key);
}

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