Question

我在这里要做的是从txt文件中删除最长的行。代码完成它的工作，但我也需要删除多个“最长行”和空白行。关于如何做的任何想法？

代码在C＃中

    namespace _5_2
    {
    //------------------------------------------------------------
    class Program
    {
         const string CFd = "..\\..\\U1.txt";
         const string CFr = "..\\..\\Results.txt";
         static void Main(string[] args)
         {
             int nr;
             Read(CFd, out nr);
             Print(CFd, CFr, nr);
             Console.WriteLine("Longest line nr. {0, 4:d}", nr + 1);
             Console.WriteLine("Program done");
         }
         //------------------------------------------------------------
         /** Finds number of the longest line.
         @param fv - text file name
         @param nr - number of the longest line */
         //------------------------------------------------------------
         static void Read(string fv, out int nr)
         {
             string[] lines = File.ReadAllLines(fv, Encoding.GetEncoding(1257));
             int ilgis = 0;
             nr = 0;
             int nreil = 0;
         foreach (string line in lines)
         {
            if (line.Length > ilgis)
               {
                  ilgis = line.Length;
                   nr = nreil;
               }
              nreil++;
          }
        }
         static void Print(string fv, string fvr, int nr)
         {
             string[] lines = File.ReadAllLines(fv, Encoding.GetEncoding(1257));
             int nreil = 0;
             using (var fr = File.CreateText(fvr))
             {
                 foreach (string line in lines)
                 {
                     if (nr != nreil)
                     {
                         fr.WriteLine(line);
                     }
                     nreil++;
                 }
             }
         }
      }
  }

Answer 1

我建议使用LINQ。利用.Max扩展方法并迭代字符串数组。

string[] lines = { "1", "two", "three" };
var longestLine = lines.Max(line => line.Length);
var revised = lines.Where(line => line.Length < longestLine).ToArray();

修订后的变量将包含一个字符串数组，该数组排除行数最长的行。

Answer 2

读取行，过滤掉空行和10条最长行，写入行：

     string[] lines = File.ReadAllLines(inputFile, Encoding.GetEncoding(1257));
     var filtered = lines
         .Where(line => line.Length > 0) // remove all empty lines
         .Except(lines.OrderByDescending(line => line.Length).Take(10)); // remove 10 longest lines
     File.WriteAllLines(outputFile, filtered);

Answer 3

您可以识别最长的行，然后遍历列表，删除所有长度。要删除空的，你可以测试String.IsNullOrWhiteSpace。

像（伪代码）：

     foreach (string line in lines)
     {
        if (String.IsNullOrWhiteSpace(line)) 
        {
            lines.Delete(line);
            Continue;
        }
        if (line.Length >= longestLine) // ">=" instead of "==" just to be on the safe side
        {
           lines.Delete(line);
        }
    }

从txt删除最长行

3 个答案: