如何使用c#按字母顺序对文本文件进行排序

Question

it prints all the names from last name to fist in the text file but i am stuck trying to print it in alphabetical order by last name

here is the code i have so far:

namespace cse1302_Lecture18_FileIO_Prez
{
    class Program
    {
        static void Main(string[] args)
        {
            StreamReader sr = new StreamReader("NameInput.txt");  //if file in bin/debug

            char[] delims = {','};

            //string[] names = {"",""};

            while(!sr.EndOfStream)
            {
                string data_line = sr.ReadLine();
                //names = data_line.Split(delims);
                Console.WriteLine(data_line);

            }
            sr.Close();
        }
    }

}

Answer 1

Try using LINQ. I've assumed here that you file contains two fields per line delimited with a comma, where the first is the First Name and the second the Surname.

var lines = System.IO.File.ReadLines("NameInput.txt");
var linesOrderedBySurname = lines.OrderBy((p) => p.Split(',')[1]).ToList();

Answer 2

First store the names into a list , then sort them based on last name like:

var names = new List<string>();
while(!sr.EndOfStream)
{
   names.Add(sr.ReadLine());
}

names.Sort((x, y) => x.Split(',')[1].CompareTo(y.Split(',')[1]));

Then just display list items in the console.

foreach(var name in names)
    Console.WriteLine(name);

This assumes that last name comes after first name and they are delimited with a comma .

Answer 3

Try to use File.ReadAllLines instead of StreamReader you need to load all lines of the file and then use LINQ to order them

 static void Main(string[] args)
            {
                var lastNames = File.ReadAllLines("yourtxtfile.txt").OrderBy(line => line.Split(',')[1]);    
            }