读取要合并的多个文本文件的相应行

Question

Firstly, I'm new to C# and I'm having a hard time figuring out how I'd go about doing this.

Basically, I have multiple text files all with their own types of data. My aim is to read the first line of each of these files and combine them into one string so that I can sort them later by their respective days.

For example, in the first line of each file there could be the values...

• File 1: 16/02/15
• File 2: Monday
• File 3: 75.730
• File 4: 0.470
• File 5: 75.260
• File 6: 68182943

So I'd like to combine them in a string like so "16/02/15 Monday 75.730 0.470 75.260 68182943"

I'd also want to do this for the second, third, fourth line etc. There are a total of 144 entries or lines.

Here is the code I have so far. I'm unsure if I'm on the right track.

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

namespace BankAlgorithms
{
    class Algorithms
    {
        static void Main(string[] args)
        {
            //Saves each individual text file into their own string arrays.
            string[] Day = File.ReadAllLines(@"C:\Users\computing\Desktop\algorithms\CMP1124M_Assigment_Files\Day.txt");
            string[] Date = File.ReadAllLines(@"C:\Users\computing\Desktop\algorithms\CMP1124M_Assigment_Files\Date.txt");
            string[] Close = File.ReadAllLines(@"C:\Users\computing\Desktop\algorithms\CMP1124M_Assigment_Files\SH1_Close.txt");
            string[] Diff = File.ReadAllLines(@"C:\Users\computing\Desktop\algorithms\CMP1124M_Assigment_Files\SH1_Diff.txt");
            string[] Open = File.ReadAllLines(@"C:\Users\computing\Desktop\algorithms\CMP1124M_Assigment_Files\SH1_Open.txt");
            string[] Volume = File.ReadAllLines(@"C:\Users\computing\Desktop\algorithms\CMP1124M_Assigment_Files\SH1_Volume.txt");

            //Lists all files currently stored within the directory
            string[] bankFiles = Directory.GetFiles(@"C:\Users\computing\Desktop\algorithms\CMP1124M_Assigment_Files");

            Console.WriteLine("Bank Files currently saved within directory:\n");
            foreach (string name in bankFiles)
            {
                Console.WriteLine(name);
            }

            Console.WriteLine("\nSelect the day you wish to view the data of (Monday-Friday). To view a grouped \nlist of all days, enter \"Day\"\n");
            string selectedArray = Console.ReadLine();

            if (selectedArray == "Day")
            {
                Console.WriteLine("Opening Day File...");
                Console.WriteLine("\nDays grouped up in alphabetical order\n");

                var sort = from s in Day
                           orderby s
                           select s;
                foreach (string c in sort)
                {
                    Console.WriteLine(c);
                }
            }
            Console.ReadLine();
        }
    }
}

Answer 1

Access your file strings from a collection, use this code to read from each file and use a StringBuilder to build your string.

Read only the first few lines of text from a file

var builder = new StringBuilder();
foreach(var file in fileList)
{
    using (StreamReader reader = new StreamReader(file))
    {
        builder.Append(reader.ReadLine());
    }
}

return builder.ToString();

Answer 2

You could use following approach: put all in an string[][] first, then it's easier:

string[][] all = { Day, Date, Close, Diff, Open, Volume };

To get the minimum length of all:

int commonRange = all.Min(arr => arr.Length);

Now this is all you need:

string[] merged = Enumerable.Range(0, commonRange)
    .Select(i => string.Join(" ", all.Select(arr => arr[i])))
    .ToArray();

This is similar to a for -loop from 0 to commonRange where you access all arrays with the same index and use String.Join to get a single string from all files' lines.

---

Since you have commented that you want to merge only the lines of a specific day:

var lineIndexes = Day.Take(commonRange)
    .Select((line, index) => new { line, index })
    .Where(x => x.line.TrimStart().StartsWith("Monday", StringComparison.InvariantCultureIgnoreCase))
    .Select(x => x.index);

string[] merged = lineIndexes
    .Select(i => string.Join(" ", all.Select(arr => arr[i])))
    .ToArray();

Answer 3

So this might be a little more than you strictly need, but I think it'll be robust, quite flexible and be able to handle huge files if need be.

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

namespace ConsoleApplication2
{
class Program
{
    private static void Main(string[] args)
    {
      //  const string folder = @"C:\Users\computing\Desktop\algorithms\CMP1124M_Assigment_Files";
        const string folder = @"C:\Temp\SO";
        var filenames = new[] { @"Date.txt", @"Day.txt", @"SH1_Close.txt", @"SH1_Diff.txt", @"SH1_Open.txt", @"SH1_Volume.txt" };

        var dataCombiner = new DataCombiner(folder, filenames);
        var stockParser = new StockParser();
        foreach (var stock in dataCombiner.GetCombinedData(stockParser.Parse)) //can also use where clause here
        { 
            if (ShowRow(stock))
            {
                var outputText = stock.ToString();
                Console.WriteLine(outputText);
            }
        }

        Console.ReadLine();
    }

    private static bool ShowRow(Stock stock)
    {
        //use input from user etc...
        return     (stock.DayOfWeek == "Tuesday" || stock.DayOfWeek == "Monday")
                && stock.Volume > 1000 
                && stock.Diff < 10; // etc
    }
}

internal class DataCombiner
{
    private readonly string _folder;
    private readonly string[] _filenames;

    public DataCombiner(string folder, string[] filenames)
    {
        _folder = folder;
        _filenames = filenames;
    }

    private static IEnumerable<string> GetFilePaths(string folder, params string[] filenames)
    {
        return filenames.Select(filename => Path.Combine(folder, filename));
    }

    public IEnumerable<T> GetCombinedData<T>(Func<string[], T> parserMethod) where T : class
    {
        var filePaths = GetFilePaths(_folder, _filenames).ToArray();
        var files = filePaths.Select(filePath => new StreamReader(filePath)).ToList();

        var lineCounterFile = new StreamReader(filePaths.First());
        while (lineCounterFile.ReadLine() != null)// This can be replaced with a simple for loop if the files will always have a fixed number of rows
        {
            var rawData = files.Select(file => file.ReadLine()).ToArray();
            yield return parserMethod(rawData);
        }
    }
}

internal class Stock
{
    public DateTime Date { get; set; }
    public string DayOfWeek { get; set; }
    public double Open { get; set; }
    public double Close { get; set; }
    public double Diff { get; set; }
    public int Volume { get; set; }

    public override string ToString()
    {
        //Whatever format you want
        return string.Format("{0:d} {1} {2} {3} {4} {5}", Date, DayOfWeek, Close, Diff, Open, Volume);
    }
}

internal class StockParser
{
    public Stock Parse(string[] rawData)
    {
        //TODO: Error handling required here
        var stock = new Stock();
        stock.Date = DateTime.Parse(rawData[0]);
        stock.DayOfWeek = rawData[1];
        stock.Close = double.Parse(rawData[2]);
        stock.Diff = double.Parse(rawData[3]);
        stock.Open = double.Parse(rawData[4]);
        stock.Volume = int.Parse(rawData[5]); 
        return stock;
    }

    public string ParseToRawText(string[] rawData)
    {
        return string.Join(" ", rawData);
    }
}
}

PS:
Instead of reading it from the file, I'd rather also calculate the DayOfWeek from the Date. Also be careful when parsing dates from a different locale (eg. USA vs UK). If you have an option I'd only use the ISO 8601 datetime format.