Thread: Problems with File Reader (Strings and 2D Array Storage)

Okay. I apologise if this is in the wrong section ^^

The assignment that I have been given asks me to use a .txt file (that contains 7 heats, each with 8 runners with their times, nationalities, numbers etc) and read it contents, I have to take the various values (names, times, nationalities etc) and store them suitably in an Array. I then have to present a way to print out the data in particular order...ie. Runners who have the fastest time.

This may sound odd and I would like to clarify that I do NOT want this 'completed for me'.
All I require are the tools so I can do it myself ^^

My tutor was very vague in regards to using the FileReader and I'm having trouble getting it to work.
I can't seem to work it out, not only that but I need to store Ints, Floats and Strings.

My plan is to store all the standard info (name, nat, etc) as Strings in a 2-D array.
ie. Array [1][7] will give me the info for the first heat and runner number 7 (I'm ignoring array 0 for ease of access).

But, to help do this, when I ever get the FileReader to work I will also need to be able to skip over values in the .txt file so that I am able to store their Race Times in a separate array of doubles.

Follow me so far?

Okay, well, I guess I'll post up my code...its 'bitty' atm, but I'd ask you to direct your attention to the class times, thats where I'm working first of all (to get used to FileReader I'll work on storing the TIMEs as doubles to begin with)

Please be gentle with me -- I've only be studying this for a few months ^^

package coursework1;
 
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.util.Scanner;
 
public class Main {
 
    public static void main(String[] args) throws FileNotFoundException {
        //TO DO///////////////////////////////////
        //READ IN DATA and STORE                //
        //PRINT DATA                            //
        //PRINT Fastest 3 Runners from Each Heat//
        //////////////////////////////////////////
        Main.times(args);
 
//        FileReader frName = new FileReader("osaka.dat");
//        Scanner infile = new Scanner (frName);
//
//        String test = infile.nextLine();
//        System.out.println(test);
//        infile.close();
 
    }
 
    public static void athlete(String[] args) throws FileNotFoundException {
 
        String[][] HeatNfo = new String[8][9];
 
//        FileReader frName = new FileReader("osaka.txt");
//        Scanner infile = new Scanner (frName);
//
//        String test = infile.nextLine();
//        System.out.println("Test");
//        infile.close();
 
    }
 
    public static void times(String[] args) throws FileNotFoundException {
        //Read in times and store them in an array
        int[][] HeatTime = new int[8][9];
 
        FileReader frTime = new FileReader("osaka.txt");
        Scanner infile = new Scanner(frTime);
 
        for (int counter = 0; counter < 25; counter++) {
            //infile.skip(long n);
            HeatTime[0][counter] = infile.nextInt();
 
 
 
        }
        infile.close();
 
 
    }
 
    {//Array of Strings.
//First array postion will store the heats.
//The next array within this will store the racers within the heats.
//The third directory in the array will store the racers info in this order:
//Lane, Num, Name and Nat.
//For example: [2][7][3] will return Heat 2, Racer 7, Name (Martyn Rooney)
//I will store the times in another class seperatly as Doubles.
    }
 
    public static void display(int x[][]) {
        for (int row = 0; row < x.length; row++) {
            for (int column = 0; column < x[row].length; column++) {
                System.out.print(x[row][column] + "\t");
            }
            System.out.println();
 
        }
    }
    //This will display all results in a 2-D Array
}

The txt file: osaka.txt (also saved as a .dat)

 Heat 1
  Lane    num   Name                    Nat   Time
   1      334   John Steffensen         AUS   44.82
   2      500   Takeshi Fujiwara        ESA   46.92
   3      651   Dim�trios R�gas         GRE   46.22
   4      352   Chris Brown             BAH   44.5
   5      1050  Rennyuow                TRI   45.7
   6      491   Arismendy Peguero       DOM   44.92
   7      897   Marcin Marciniszyn      POL   45.83
   8      626   Bastian Swillims        GER   45.44
 
 Heat 2
  Lane    num   Name                    Nat   Time
   1      351   Avard Moncur            BAH   45.27
   2      571   Brice Panel             FRA   46.02
   3      1166  Lewis Banda             ZIM   45.47
   4      915   F�lix Mart�nez          PUR   46.86
   5      1151  Jeremy Wariner          USA   45.1
   6      684   David Gillick           IRL   45.35
   7      595   Martyn Rooney           GBR   45.47
   8      846   Herm�n L�pez            NCA   50.72
 
 Heat 3
  Lane    num   Name                    Nat   Time
   1      905   Rafal Wieruszewski      POL   45.94
   2      489   Carlos Santa            DOM   45.99
   3      658   Alleyne Francique       GRN   44.95
   4      1001  Abdulla Mohamed Hussei  SOM   50.54
   5      713   Ricardo Chambers        JAM   45.34
   6      561   Leslie Djhone           FRA   45.17
   7      345   Clemens Zeller          AUT   46.06
   8      596   Andrew Steele           GBR   45.54
 
 Heat 4
  Lane    num   Name                    Nat   Time
   1      349   Andrae Williams         BAH   45.31
   2      1037  Johan Wissman           SWE   44.94
   3      1080  Andr�s Silva            URU   46.79
   4      1120  LaShawn Merritt         USA   44.78
   5      1168  Young Talkmore Nyongan  ZIM   45.4
   6      834   Dalibor Spasovski       MKD   48.63
   7      381   Gakologelwang Masheto   BOT    0.0
   8      842   Eric Milazar            MRI   46.55
 
 Heat 5
  Lane    num   Name                    Nat   Time
   1      584   Timothy Benjamin        GBR   45.44
   2      451   Gary Kikaya             COD   45.21
   3      313   Nicolau Palanca         ANG   48.6
   4      486   Chris Lloyd             DMA   45.46
   5      932   Ioan Lucian Vieru       ROM   46.78
   6      706   Sanjay Ayre             JAM   45.28
   7      954   Vladislav Frolov        RUS   45.69
   8      366   Mathieu Gnaligo         BEN   47.51
 
 Heat 6
  Lane    num   Name                    Nat   Time
   1      708   Michael Blackwood       JAM   45.44
   2      1141  Angelo Taylor           USA   45.13
   3      735   Yuki Yamaguchi          JPN   46.28
   4      380   California Molefe       BOT   45.36
   5      455   Nery Brenes             CRC   45.01
   6      646   Jonathon Lavers         GIB   47.97
   7      999   Ivano Bucci             SMR   48.07
   8      459   William Collazo         CUB   45.29
 
 Heat 7
  Lane    num   Name                    Nat   Time
   1      1049  Ato Modibo              TRI   45.22
   2      891   Daniel Dabrowski        POL   45.5
   3      329   Sean Wroe               AUS   45.39
   4      649   Dim�trios Gr�valos      GRE   46.94
   5      1161  Moses Kamut             VAN   48.9
   6      690   Andrea Barberi          ITA   45.74
   7      1114  Lionel Larry            USA    0.0
   8      425   Tyler Christopher       CAN   45.15

...and to save confusion...THIS is my assignment.
Hopefully it will make more sense than my own ramblings...

ECSC401 Programming Methodology (Java) 
Semester 1, 2009/10
Coursework
Deadline : Tuesday 12th January 2010
Value : 20 marks
Requirements
The results of the mens 400m heats from the 2007 IAAF World Championships in Osaka have been stored in the file osaka.txt. For each heat, the file contains the following information about each athlete: 
•	lane number 
•	competition number {worn on vest} 
•	name 
•	nationality {3 character abbreviation} 
•	time for the race {seconds} 
The fastest three athletes from each heat automatically qualified for the next round, along with the three overall fastest "losers", so that 24 athletes progressed to the next round of the competition. 
You are asked to write, in Java :
•	a method to read the data from the file and store it in a suitable way. 
•	a method which lists the fastest three athletes from one heat. 
•	a main method which uses these two methods and establishes which twenty four athletes would progress to the next round of the competition. 
N.B. It is likely that you will need a few more methods to complete this task. 
You should hand in the following at the campus office: 
•	A listing of your java program. 
•	A test plan describing the tests that you ran on the program and their results. 
Please do not include discs! They are not needed thank you. 
Marks will be lost if you do not follow the Department Coding Standard for code layout. 
 
You should also email the java source code to your tutor: 
•	Cavendish Chris Bailey 
•	Harrow Artie Basukoski

Thanks in advance for any help and advice

Review your use of the Scanner object; it will be necessary to read in all sorts of data: int's, Strings, floats, etc...you know their order based upon the file format that you have so you can utilize the appropriate Scanner methods in the appropriate order to retrieve the data (see Scanner (Java 2 Platform SE 5.0)). Further, rather than writing a deterministic approach to reading the file (aka a method that reads only a single file with the same length and identical format), I'd say its good practice to step back a second a jot down a general file format and use this as the basis for how you read the file (for example, what if you wish to read more than one file and you do not know how many heats it has, or how many competitors there are in each heat?). This may be more advanced than the assignment is asking, but doing it this way will allow your method to read not just one file, but many - the more adaptable the format you lay out the better it will be for reading different types of files.
As far as storage, because Java is object oriented perhaps a more ordered and readable method to place the data into memory would be to create objects - say a class Competitor and a class Heat, and store them in some sort of array.

@copeg thanks for such a detailed reply ^^
Hm you do have a point. It would be far better practice to design code that would be able to accept files of different names and with different number of heats, these variables could easily be taken from User Input. I still can't get the File Reader code to work and actually store anything ¬_¬; I really can't see what I'm doing wrong.

Hey
I am not fully sure why you are going to ask the user to enter the number of heats and athletes, because even if they enter wrong values in, the reader will still display the full text.
I think this could lead to a bug at a later stage or so, but I'm not sure myself.

Originally Posted by teen-omar

Hey
I am not fully sure why you are going to ask the user to enter the number of heats and athletes, because even if they enter wrong values in, the reader will still display the full text.
I think this could lead to a bug at a later stage or so, but I'm not sure myself.

My intention is to produce a program that can read in a file with more than the standard heats and nos of athletes and print out the 'winners' from each heat.

As I mentioned, as useful as the code was that you provided, I need to read in the data more specifically and store it all in suitable arrays so that I can print it out in an order or at request.

Printing the ENTIRE document, while useful, doesn't help me very much with this assignment as a whole.

Thanks anyway

Apologies for double posting... I'm making some head way with the program...
However still having trouble getting and storing doubles (and data in general ¬_¬

Heres the newest code...

package coursework1;
 
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Scanner;
 
public class Main2 {
        static String fileName = "";
        static int noOfHeats = 0;
        static int noOfCompet = 0;
        static int nameNoEx = 0;
        static int totalCompet = noOfCompet * noOfHeats;
        static double [] heatTimes = new double [totalCompet];
 
    public static void main (String[] args) throws FileNotFoundException{
    Main2.body(args);
    Main2.readTimes(args);
    }
 
    private static void body (String[] args) throws FileNotFoundException{
 
        InputStreamReader input = new InputStreamReader(System.in);
        BufferedReader reader = new BufferedReader(input);
        System.out.println("Please type your file name (including the Extension): ");
        // read in user input
        try {
            fileName = reader.readLine();
            }
        catch(Exception e){}
 
////////////////////////////////////////////////////////////////////////////////
 
        System.out.println("Please enter the number of heats: ");
        Scanner input1 = new Scanner(System.in);
        noOfHeats = input1.nextInt();
 
////////////////////////////////////////////////////////////////////////////////
 
        System.out.println("Please enter the number of Competitors PER HEAT: ");
        Scanner input2 = new Scanner(System.in);
        noOfCompet = input2.nextInt();
 
////////////////////////////////////////////////////////////////////////////////
 
        System.out.println("\n==CONFIRMATION==\nFile Name: " + fileName + "\nNo. Heats: " +
                noOfHeats +  "\nNo. Competitors per Heat: "
                + noOfCompet + "\n==END CONFIRMATION==\n\n");
 
////////////////////////////////////////////////////////////////////////////////
        //This will Print the file in its entirety. I will keep it here should I need it
//        try {
//            BufferedReader br = new BufferedReader(new FileReader(fileName));
//            String strLine;
//            while ((strLine = br.readLine()) != null) {
//                System.out.println(strLine);
//            }
//            br.close();
//        } catch (Exception exc) {
//            System.err.println("Error: " + exc.getMessage());
//        }
 
    }
 
    [B]private static void readTimes(String[]args) {
        //Buffered Reader to readLine(), then parse into Double
    for (int counter = 0; counter < heatTimes.length; counter++){
            try {
            BufferedReader reader = new BufferedReader(new FileReader(fileName));
            String input = reader.readLine();
 
            double number = Double.parseDouble(input);
            heatTimes[counter]=number;
            System.out.print(heatTimes[counter] + "/n");
            reader.close();
 
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
Main2.displayHeatTimes(args);
    }[/B]
 
    private static void display2d(int x[][]) {
        for (int row = 0; row < x.length; row++) {
            for (int column = 0; column < x[row].length; column++) {
                System.out.print(x[row][column] + "\t");
            }
            System.out.println();
 
        }
    }
 
    private static void displayHeatTimes(String[] args){
        //a method to display the values in heatTimes array
        int sum = 0;
for (int counter =0; counter<heatTimes.length; counter++){
sum += heatTimes[counter];
System.out.println(counter + "\t" + heatTimes[counter]);
}
    }
 
}

I'm currently working on "private static void readTimes(String[]args)" , when I run the program as it is currently this method seems to do 'nothing'. Can anyone see something I can't. Okay, that's a stupid question since everyone on here is a hellava lot better at this than me .. I'm trying though!!

Thanks.

Hey
Are there any other classes you have created for which the code isn't displayed?
Because this might give us a clue as to what to do next.
Been looking at your code, and the display2d method isn't doing anything at the moment.
If you can, put up the rest of the codes so that we can have a further look.

^Actually that's the whole code.
I originally intended to use 2 Dimensional Arrays to store my info, and that code would've showed all the values in a 2D array.
I kept it there as reference for the time being, just incase I reverted back to using 2D arrays. (But I have got to store stuff first lol).

So yeah, that's the whole code currently, ignore display2d if it helps, as you say it does nothing and there are no other methods or classes involved yet.

My current dilemma is situated in readTimes (in BOLD)...hope that helps!
Thanks

With your code, have you tested whether it saves the Heat times into array? made any checks like "System.out.print..."
Always make sure that the Array works in terms of storing the data
So are you saying that you're not intending to use the 2D array now or what is the case?
Been looking through your code now for more than 1/2 hour and still can't seem to fint eh missing puzzle piece....
I'll update you on anything new ;-)

At the end of readTimes I called the method "Main2.displayHeatTimes(args);", this is a simple method that displays the all values in an array. Its worked on the dozens of other programs I have made which have used arrays and alas, it just seems to do 'nothing' O_o

I really appreciate the help, thank you very very much

hey k0209, any chance of uploading the account.dat file so we can check out the way he laid it out in the file?
Also, i think you forgot to post up a separate class file which holds the information of how to access the methods.
So that, so we can have a further look.
BTW, are you 100% sure your teacher said that this is all you need to complete your assignment???
Because I'm not seeing any BufferedReader so i'm kind of wondering right now.....hmmmm

The distance between num and name isn't always same, but it is always greater than 2, so elaborate on that ;-)
but between Nat and time there are always 3 spaces, so have you taken that into consideration (sorry if you already have)

I have tried, do you think the method mentioned in my above edit 1.2 is a good way to go?

lol, seems like you want to experiment a lot with the java classes.
how come you are jusing the Logger class now?
If you want to split up the data, you could use a .trim for it.
Here is a code i quickly made for your task, what it does it reads the lines and then splits them in seperate lines
hope this should help you immensely ;-)

try 
		{
			FileInputStream inStream = new FileInputStream("osaka.txt");
			DataInputStream in = new DataInputStream(inStream);
			BufferedReader br = new BufferedReader(new InputStreamReader(in));
			String line;
 
			// create an array of heats for size 7
			// Heat[] heats = new Heat[7];
			boolean firstHeat = true;
			while ((line = br.readLine()) != null) 
			{
				if (!line.equals(""))
				{
					if (line.trim().startsWith("Heat")){
						if (firstHeat){
							firstHeat = false;
						} else {
							//add old heat to the heat array	
						}
						//create a new heat object
					} else
					{
						 //create new athlete object and add it to the heat
						String [] lol = line.trim().split("\\b\\s{2,}\\b");
						for (int i=0; i < lol.length; i++)
						{
							System.out.println(lol [i]);
						}
						System.out.println(line);
					}
 
				}
 
			}
 
			in.close();
		} 
		catch (Exception e) 
		{
			System.err.println("Error: " + e.getMessage());
		}
	}
}

Wow! You wrote that?!
I wish I had that kinda know how here! ^__^

If I'm honest, I love programming! I want to know all there is to it, but since I've only been studying for a short while I'm held back by 'what I actually know' lol

That code you provided looks perfect! I'll implement it and see how it goes lol

This is what I came up with before your reply ^^
It stores each line in a different postion in a ArrayList.
If I could work out how to split/store them from there i'd be on easy street lol

Thank you so much for your help!

    private static void readLineIn (String[]args) throws FileNotFoundException {
        //Buffered Reader to readLine()
        BufferedReader reader = new BufferedReader(new FileReader(fileName));
        try {
            while (reader.ready()) {
                for (String field : reader.readLine().split("\n")) {
                    // do whatever
                    list.add(field);
                   }
            }
        } catch (IOException ex) {
            Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
        }
        System.out.println(list);
                }

Originally Posted by teen-omar

Let me know when your code is perfected, would love to see how it ends up as ;-)
BTW, the code you posted, i don't seem to understand where you got the "list" from.
Make sure you initialize if first before you use it

Naturally!
Although I'd bet I'll be back for help before the end of the day! lol

Its probably just me being dense, but I can't seem to fit this into my code.
While I have been able to call it, I'm a bit at a loss as to how I go about retrieving the various values and also to start arranging them lol

Sorry, I feel like such a dunce!

package coursework1;
 
import java.lang.*;
import java.util.*;
import java.util.logging.*;
import java.io.*;
//import java.util.ArrayList;
//import java.util.List;
 
 
public class Main {
    //Golbal variables to be accessed by most of my methods
    static String fileName = "";//The file that the user wants to access
    static List list = new ArrayList();
    static List newList = new ArrayList();
 
    public static void main (String[] args) throws FileNotFoundException{
    Main.body(args);
           }
 
    private static void body (String[] args) throws FileNotFoundException{
    //the bulk of the code/calling will go here, so that main is left with
    //as few calls as possible for ease.
        Main.getFileName(args);
        //Main.readLineInv1(args);
        Main.readLineInv2(args);
 
    }
 
    private static void getFileName (String[] args)throws FileNotFoundException{
        InputStreamReader input = new InputStreamReader(System.in);
        BufferedReader reader = new BufferedReader(input);
        System.out.println("Please type your file name (including the Extension): ");
        // read in user input
        try {
            fileName = reader.readLine();
            }
        catch(Exception e){}
        System.out.println("\n====CONFIRMATION====\nFile Name: " + fileName + "\n==END CONFIRMATION==\n\n");
            }
 
    private static void printFile (String[]args) throws FileNotFoundException{
         //This will Print the file in its entirety.
         try {
            BufferedReader br = new BufferedReader(new FileReader(fileName));
            String strLine;
            while ((strLine = br.readLine()) != null) {
                System.out.println(strLine);
            }
            br.close();
        } catch (Exception exc) {
            System.err.println("Error: " + exc.getMessage());
        }
    }
 
    private static void readLineInv1 (String[]args) throws FileNotFoundException {
        //Buffered Reader to readLine() then stores in Array List
        BufferedReader reader = new BufferedReader(new FileReader(fileName));
        try {
            while (reader.ready()) {
                for (String field : reader.readLine().split("\n")) {
                    // do whatever
                    list.add(field);
 
                   }
            }
        } catch (IOException ex) {
            Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
        }
        System.out.println(list);
        System.out.println("------------");
                }
 
   [B] private static void readLineInv2 (String[] args) throws FileNotFoundException{
       //it reads the lines and then splits them in seperate lines
        try {
            FileInputStream inStream = new FileInputStream(fileName);
            DataInputStream in = new DataInputStream(inStream);
            BufferedReader br = new BufferedReader(new InputStreamReader(in));
            String line;
 
            // create an array of heats for size 7
            //Heat[] heats = new Heat[7];
            boolean firstHeat = true;
            while ((line = br.readLine()) != null) {
                if (!line.equals("")) {
                    if (line.trim().startsWith("Heat")) {
                        if (firstHeat) {
                            firstHeat = false;
                        } else {
                            //add old heat to the heat array
                        }
                        //create a new heat object
                    } else {
                        //create new athlete object and add it to the heat
                        String[] lol = line.trim().split("\\b\\s{2,}\\b");
                        for (int i = 0; i < lol.length; i++) {
                            System.out.println(lol[i]);
                        }
                        System.out.println(line);
                    }
 
                }
 
            }
            in.close();
        } catch (Exception e) {
            System.err.println("Error: " + e.getMessage());
        }
 
}[/B]
 
 
	}

here's the thing
you are trying to use your reading in method, along with the one i provided
use the one i gave you, and build on it the arrays and stuff you gotta do
so get rid of your reading in method of the file and work from there ;-)