Friday Programming Quiz [modified]

[Daniel Grunwald]

using System.Linq;
class Program {
public static void Main(string[] args) {
args.Select(
fileName => System.IO.File.ReadAllLines(fileName).Select(
line => new { ID = int.Parse(line.Split(',')[0]), Name = line.Split(',')[1]}
))
.Aggregate((a, b)=>a.Concat(b))
.OrderBy(a=>a.ID).ToList().ForEach(a=>System.Console.WriteLine("{0},{1}", a.ID, a.Name));
}
}

If you require that the output is written to a file, use this:

	System.IO.File.WriteAllLines("output.txt", args.Select(
		fileName => System.IO.File.ReadAllLines(fileName).Select(
			line => new { ID = int.Parse(line.Split(',')\[0\]), Name = line.Split(',')\[1\]}
		))
		.Aggregate((a, b)=>a.Concat(b))
		.OrderBy(a=>a.ID).Select(a=>string.Format("{0},{1}", a.ID, a.Name)).ToArray());

---

Last modified: 8mins after originally posted --

[ToddHileHoffer]

I wrote an application to do this. Front end and all in 7 minutes. I could have used a hash-table or arraylist or whatever but I used ado.net because that's the kind of guy I am. using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Text; using System.Windows.Forms; namespace WindowsApplication1 { public partial class Form1 : Form { DataTable dt; Int32 FilesRead = 0; private void AddFileToDataTable(System.IO.Stream fileStream) { System.IO.StreamReader sr = new System.IO.StreamReader(fileStream); string input; DataRow dr; while ((input = sr.ReadLine()) != null) { string[] s = input.Split(new char[] { ',' }); dr = dt.NewRow(); dr["ID"] = int.Parse(s[0]); dr["Name"] = s[1]; dt.Rows.Add(dr); } sr.Close(); } public Form1() { InitializeComponent(); dt = new DataTable(); DataColumn dc; dc = new DataColumn(); dc.DataType = System.Type.GetType("System.Int32"); dc.ColumnName = "ID"; dt.Columns.Add(dc); dc = new DataColumn(); dc.DataType = System.Type.GetType("System.String"); dc.ColumnName = "Name"; dt.Columns.Add(dc); } private void button1_Click(object sender, EventArgs e) { this.openFileDialog1.ShowDialog(); System.IO.Stream sr = System.IO.File.Open(this.openFileDialog1.FileName, System.IO.FileMode.Open); AddFileToDataTable(sr); FilesRead += 1; this.label1.Text = "Files Read:" + FilesRead.ToString(); } private void button2_Click(object sender, EventArgs e) { this.saveFileDialog1.ShowDialog(); DataView dv = new DataView(dt); dv.Sort = "ID ASC"; dt = dv.ToTable(); StringBuilder sb = new StringBuilder(); foreach (DataRow r in dt.Rows) { sb.Append(r[0].ToString() + "," + r[1].ToString() + Environment.NewLine); } System.IO.File.WriteAllText(this.saveFileDialog1.FileName, sb.ToString()); } } }

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[PIEBALDconsult]

What about duplicates?

[Chris Losinger]

this one feels too much like actual work

image processing toolkits | batch image processing

[Rama Krishna Vavilala]

There are no duplicates. Assume unique values

Co-Author ASP.NET AJAX in Action

[Minosknight]

00110001001011000100001101101000011100100110100101110011001000000 10011010110000101110101011011100110010001100101011100100000110100 00101000110110001101010011010100110110001011000100001101101000011 10010011010010111001101110100011010010110000101101110001000000100 01110111001001100001011101010111001100001101000010100011011100110 11100110100001100010010110001001010011011110110100001101110001000 00010100110110100101101101011011010110111101101110011100110010000 00010111100100000011011110111010101110100011011000110000101110111 00100000011100000111001001101111011001110111001001100001011011010 11011010110010101110010000011010000101000110001001101010011001100 11100000110011001011000101001001100001011011010110000100100000010 01011011100100110100101110011011010000110111001100001001000000101 01100110000101110110011010010110110001100001011011000110000100001 10100001010001100100011000000110010001101000011100000101100010011 10011010010111001101101000011000010110111001110100001000000101001 10110100101110110011000010110101101110101011011010110000101110010 00001101000010100011001100110110001110000011000000110011001011000 10011010110000101110010011000110010000001000011011011000110100101 100110011101000110111101101110

Think of it this way...using a Stradivarius violin to pound nails should not be considered a sound construction technique

[Luis Alonso Ramos]

Can anyone do this help me do this for my homework? It's due in two hours and I've had all the semester!! Please help urgent!! ;P

Luis Alonso Ramos Intelectix Chihuahua, Mexico

My Blog!

[PIEBALDconsult]

Rama Krishna Vavilala wrote:

Assume

That's a naughty word.

[Daniel Grunwald]

Rama Krishna Vavilala wrote:

No duplicates!

Does this mean the input files do not contain duplicates, or duplicates need to be removed? In my solution, put a ".Distinct()" between the Aggregate line and the Sort+Output line if you need to remove duplicates.

[Rama Krishna Vavilala]

Yes! It is close. All the quizzes are based on actual work I did. It is based on a IIS log analyzer utility I once wrote which sorted log records from different servers into one file. Except that the actual program was far more complex as it had to read large files in buffers and merge them.

Co-Author ASP.NET AJAX in Action

[PIEBALDconsult]

Oh, now that's got me thinking of Douglas Adams again, Dirk Gently in fact: The program kgvclsg lgzszsil gvhzxido;vzxdl'vcbx gcb ;klh gjl;ghilsfdghb kZG l gh will perform the task, we just need to find a compiler for it! :laugh:

[Rama Krishna Vavilala]

No your solution is correct! There will be no duplicates.

Co-Author ASP.NET AJAX in Action

[Luis Alonso Ramos]

I need to start learning LINQ :doh: I'll give you a 5 and suppose that it actually works :)

Luis Alonso Ramos Intelectix Chihuahua, Mexico

My Blog!

[PIEBALDconsult]

OK, then my version of sort does. :-D

[Gary Wheeler]

Watch it; remember the kid-sister rule in the Lounge.

---

Software Zen: delete this;

[Minosknight]

precisely, I was just being lame and put the desired end result into a text to binary converter. I suppose you could just do it the other way around and TAH-DAH!;P

Think of it this way...using a Stradivarius violin to pound nails should not be considered a sound construction technique

[Daniel Grunwald]

My first solution requires loading everything into memory (ReadAllLines/WriteAllLines uses arrays, OrderBy requires having the whole list in memory). Here is another LINQ solution that uses a custom functions for reading/writing files and merging the enumerables:

using System;
using System.IO;
using System.Collections.Generic;
using System.Linq;
static class Program {
public static void Main(string[] args) {
SortedMerge(args.Select(
fileName => FileReadLines(fileName).Select(
line => new { ID = int.Parse(line.Split(',')[0]), Name = line.Split(',')[1]}
)), a=>a.ID)
.Select(a=>string.Format("{0},{1}", a.ID, a.Name))
.WriteToFile("output.txt");
}

static IEnumerable<string> FileReadLines(string fileName)
{
	using (StreamReader reader = new StreamReader(fileName)) {
		string line;
		while ((line = reader.ReadLine()) != null) {
			Console.WriteLine("read " + line + " from " + fileName);
			yield return line;
		}
	}
}

static void WriteToFile(this IEnumerable<string> lines, string fileName)
{
	using (StreamWriter writer = new StreamWriter(fileName)) {
		foreach (string line in lines) {
			Console.WriteLine("write " + line + " to " + fileName);
			writer.WriteLine(line);
		}
	}
}

static IEnumerable<T> SortedMerge<T, K>(IEnumerable<IEnumerable<T>> inputs, Func<T, K> keySelector) where K : IComparable<K>
{
	var enumerators = inputs.Select(o=>o.GetEnumerator()).ToList();
	var disposables = enumerators.ToList(); // make copy of enumerators for disposing them later
	try {
		// move all enumerators on the first element
		enumerators.RemoveAll(e=>!e.MoveNext());
		while (enumerators.Count > 0) {
			int smallest = 0;
			for (int i = 1; i < enumerators.Count; i++) {
				// the the element of the current enumerator smaller than the best found so far?
				if (keySelector(enumerators\[i\].Current).CompareTo(keySelector(enumerators\[smallest\].Current)) < 0) {
					smallest = i;
				}
			}
			yield return enumerators\[smallest\].Current;
			if (!enumerators\[smallest\].MoveNext())
				enumerators.RemoveAt(smallest);
		}
	} finally {
		disposables.ForEach(d => d.Dispose());
	}
}

}

The debug output shows that the program is writing as soon as possible; written lines will be collected by the GC, so this solution can merge multi-GB files without running out of memory. Output:

C:\temp\SharpDevelop Projects\CPQ

[Tarakeshwar Reddy]

Dictionary<int, string> cpians = new Dictionary<int, string>();
List<int> keylist = new List<int>();

string strLine = "";

foreach (System.IO.FileInfo fi in new System.IO.DirectoryInfo(@"C:\quiz\").GetFiles())
{              
    using (System.IO.StreamReader sr = fi.OpenText())
    {
        while (sr.Peek() >= 0)
        {
            strLine = sr.ReadLine();
            cpians.Add(Int32.Parse(strLine.Split(',')[0]), strLine.Split(',')[1]);
            keylist.Add(Int32.Parse(strLine.Split(',')[0]));
        }
    }
}

keylist.Sort();

using (System.IO.FileStream file = new System.IO.FileStream(@"C:\TotalList.txt", System.IO.FileMode.Create, System.IO.FileAccess.Write))
{
    using (System.IO.StreamWriter sw = new System.IO.StreamWriter(file))
    {
        foreach (int key in keylist)
        {
            sw.WriteLine(key + "," + cpians[key]);
        }
    }
}

The items in the file need not be sorted for this solution.

[PIEBALDconsult]

string inline ;

System.Collections.Generic.List list =
new System.Collections.Generic.List() ;

while ( ( inline = System.Console.ReadLine() ) != null )
{
list.Add ( inline.PadLeft ( inline.Length + 16 - inline.IndexOf ( ',' ) , ' ' ) ) ;
}

list.Sort() ;

foreach ( string s in list )
{
System.Console.WriteLine ( s.TrimStart() ) ;
}

[lost in transition]

I would like to see someone right a solution in QBasic:) or Pascal:rose:. Make you own front end. Will this work.

namespace CP
{
static class Program
{
/// /// The main entry point for the application.
///
[STAThread]
static void Main()
{
PQuizOTD pqtd = new PQuizOTD();
pqtd.ReadFile(@"C:\TestData1.txt");
pqtd.ReadFile(@"C:\TestData2.txt");
pqtd.ExportToFile();
}
}
class PQuizOTD
{
private DataTable dt;

    public PQuizOTD()
    {
        dt = new DataTable();
        dt.Columns.AddRange(
                    new DataColumn\[\] { 
                        new DataColumn("ID"), 
                        new DataColumn("Name") });
    }

    public void ReadFile(string FileName)
    {
        string line;
        StreamReader sr = new StreamReader(FileName);
        while (!sr.EndOfStream)
        {
            line = sr.ReadLine();
            int index = line.IndexOf(",");
            DataRow dr = dt.NewRow();
            dr\[0\] = line.Substring(0, index);
            dr\[1\] = line.Substring(index + 1, (line.Length - index - 1));
            dt.Rows.Add(dr);
        }
    }

    public void ExportToFile()
    {
        dt.DefaultView.Sort = "Name ASC";
        dt.AcceptChanges();
        dt = dt.DefaultView.ToTable();
        StreamWriter sw = new StreamWriter(@"C:\\TestData\_Export.txt");
        for (int i = 0; i < dt.Rows.Count; i++)
        {
            sw.WriteLine(dt.Rows\[i\]\[0\].ToString() + "," + dt.Rows\[i\]\[1\].ToString());
        }
        sw.Close();
    }
}

}

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God Bless, Jason
God doesn't believe in atheist but He still loves them.