从文本文件中读取整数并将其存储在列表中

Question

I have a small text file, containing a few integers on separate lines.

I wrote the following program (just a function called ReadFromFile ) in order to read in the integers and assign them to some variables.

I wonder if I could improve it, and how? I tried reading in integers, but realized I would get errors with StreamReader , so I carried on using strings.

Is there anyway I could improve this program?

All it does is read in the following numbers, assign the first two to two variables, and put the rest in a list.

3
4
8
8
8
8
8
8

So, I will have: var1 = 3 , var2 = 4 , myList = [8,8,8,8,8,8]

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;    


namespace Practice
{
    class Program
    {
        static void Main(string[] args)
        {    
            // Read the specifications from the file.
            ReadFromFile();

            // Prevent the console window from closing.
            Console.ReadLine();
        }


        /// The function that reads the input specifications from a file.
        public static void ReadFromFile()
        {
            string localPath = @"C:\Desktop\input.txt";
            StreamReader sr = new StreamReader(localPath);

            // Read all the lines from the file into a list,
            // where each list element is one line.

            // Each line in the file.
            string line = null;

            // All lines of the file.
            List<string> lines = new List<string>();

            while ( ( line = sr.ReadLine() ) != null )
            {
                lines.Add(line);
                Console.WriteLine(line);
            }          

            // Display the extracted parameters.                
            Console.WriteLine( lines[0] + " var1");
            Console.WriteLine( lines[1] + " var2");

            // Put the rest in a separate list.
            List<int> myList = new List<int>();

            for (int i = 2; i < lines.Count; i++)
            {
                Console.WriteLine("item {0} = {1}", i-1, lines[i] );
                myList.Add( Int32.Parse( lines[i] ) );
            }

            sr.Close();
        }
    }
}

Answer 1

var vals = File.ReadAllLines(path).Select(int.Parse).ToList();

You might need a Skip(...) if you have header lines; for example to match your for(int i = 2; ...) :

var vals = File.ReadAllLines(path).Skip(2).Select(int.Parse).ToList();

Answer 2

You could write it as follow :

public static void ReadFromFile(string localPath) // paremetrizing the path for more flexibility
    {
        StreamReader sr = new StreamReader(localPath);

        // extrating the lines from the file
        List<int> lines = Regex.Split(sr.ReadToEnd(), "\r\n").Select(int.Parse).ToList();

        // we can close the reader as we don't need it anymore
        sr.Close();

        Console.WriteLine( lines[0] + " var1");
        Console.WriteLine( lines[1] + " var2");

        // removing the first 2 elements
        lines = lines.Skip(2).ToList();



        for (int i = 0; i < lines.Count; i++)
        {
            Console.WriteLine("item {0} = {1}", i-1, lines[i] );
        }

    }