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Thread: I/O Help with Collections/Ordering?

  1. #1
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    Default I/O Help with Collections/Ordering?

    I am trying to finalize a project in Java, however I am having a hard time getting the Collections.sort to work and sort my output by natural order. Basically I should be getting:

    Total properties listed: 7
    Total value of properties listed: 2120000.00

    110001
    110020
    110223
    110333
    110421
    110442
    112352

    But I am getting:

    Total properties listed: 7
    Total value of properties listed: $2120000.00

    110001
    110223
    110020
    110333
    110442
    110421
    112352

    Everything is working except for my natural ordering of the ID numbers listed at the bottom. If anyone can take a look through my code and let me know what I might be doing wrong here any help would be appreciated! Thanks!

     package kettask2pt2;
     
    import java.util.Scanner;
    import java.io.BufferedReader;
    import java.io.FileNotFoundException;
    import java.io.IOException;
    import java.io.PrintWriter;
    import java.io.FileReader;
    import java.io.File;
    import java.util.ArrayList;
    import java.util.*;
    /**
     *
     * @author Brandon
     */
     
    public class KETTask2Pt2{
       public static void main(String[] args) throws FileNotFoundException, IOException
        {
     
          // Ask for the file name listings.txt
     
            Scanner inputscan = new Scanner(System.in);
            System.out.print("Please enter listings.txt: ");
            String inputFile = inputscan.next();
     
          // Creates variables & BufferedWriters
            String line = null ;
            PrintWriter out = new PrintWriter("overview.txt");
            File input = new File(inputFile);
            BufferedReader in = new BufferedReader(new FileReader(input));
            int count = 0;
            double sum = 0;
     
          // Totals and adds properties listed and the values of the properties  
      while ((line = in.readLine())!= null)     
                {
                count++;
                String[] thelist = line.split("[\\s}]");
                Double totalvalue = Double.parseDouble(thelist[2]);
     
    	       {
                    sum+=totalvalue;
                   }        
                }
                out.println("Total properties listed:  " + count);
                out.println("Total value of properties listed: " + "$" +sum + "0" +"\n");
                in.close();
     
         //Adds the id numbers for the individual listings              
          try {
                 ArrayList<String> ids = new ArrayList<String>();
                 Scanner idscan = new Scanner((input)); 
     
               while (idscan.hasNextLine())
               {              
                 line = idscan.nextLine();
                 String[] fields = line.split("[\\s}]");
                 String idnums = (fields [0]);      
     
                       {
                        Collections.sort(ids);            
                     out.println(idnums);                      
                        in.close();
     
                       }
                    }
                }catch(Exception e){              
                       }           
                 //closes the print writer
                    out.flush();
                out.close();
            }
    }
    Last edited by BTaggar; August 26th, 2013 at 09:59 PM. Reason: code tags

  2. #2
    Super Moderator jps's Avatar
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    Default Re: I/O Help with Collections/Ordering?

    What does the file look like?

  3. #3
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    Default Re: I/O Help with Collections/Ordering?

    The file is a .txt file with the following contents

    110001 commercial 500000.00 101
    110223 residential 100000.00 101
    110020 commercial 1000000.00 107
    110333 land 30000.00 105
    110442 farm 200000.00 106
    110421 land 40000.00 107
    112352 residential 250000.00 110

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    Default Re: I/O Help with Collections/Ordering?

    Why have you declared a Scanner and 2 BufferedReaders? Especially when you don't even use the second BufferedReader. Why do you read the file twice? That's a waste of time and resources. Read the file once and process each line fully. You sort the ArrayList ids but you never insert any data into it.
    Improving the world one idiot at a time!

  5. The Following User Says Thank You to Junky For This Useful Post:

    BTaggar (August 27th, 2013)

  6. #5
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    Default Re: I/O Help with Collections/Ordering?

    The only reason I have 2 buffered readers and am wasting time and resources is because I came with this code after a lot of trial and error haha, it may seem simple, but to me this is like a foreign language I am learning... The data is inserting into the text file, and it looks like I am sorting it before I insert it, but you are saying that I am not correctly placing it into the array list before displaying it, correct?

    --- Update ---

    Also, I removed the unused BufferedReader, thanks for the heads up!

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    Default Re: I/O Help with Collections/Ordering?

    That is exactly what I am saying. Read your code carefully. Look at the input and output files. They are exactly the same. Doesn't that ring bells? What your code does is read a line of text, extracts the ID number and writes it out to the output file. Nowhere in your code do you insert data into the ArrayList or extract the data back out of the ArrayList.
    Improving the world one idiot at a time!

  8. #7
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    Default Re: I/O Help with Collections/Ordering?

    Good call, I am assuming I can add the information to the array list by using

    ids.add(idnums);

    and call it by using the

    ids.get(idnums)

    is this close?

  9. #8
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    Default Re: I/O Help with Collections/Ordering?

    What happened when you tried?

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    Default Re: I/O Help with Collections/Ordering?

    Try it an see.

    However, the get method presumably would retrieve something from the list. So what is the point if you already have it stored in the idnums variable?
    Improving the world one idiot at a time!

  11. #10
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    Default Re: I/O Help with Collections/Ordering?

    The code below I tried, and this is what I got:

    Total properties listed: 7
    Total value of properties listed: $2120000.00

    110001
    110001
    110223
    110001
    110020
    110223
    110001
    110020
    110223
    110333
    110001
    110020
    110223
    110333
    110442
    110001
    110020
    110223
    110333
    110421
    110442
    110001
    110020
    110223
    110333
    110421
    110442
    112352


         //Adds the id numbers for the individual listings              
          try {
                 ArrayList<String> ids = new ArrayList<String>();                     
                 Scanner idscan = new Scanner((input)); 
     
               while (idscan.hasNextLine())
     
     
     
               {              
                 line = idscan.nextLine();
                 String[] fields = line.split("[\\s}]");
                 String idnums = (fields [0]);  
                 ids.add(idnums);
                  Collections.sort(ids);
                       {
     
                        int arraysize = ids.size();
                             for(int i=0; i<arraysize; i++){
                           out.println(ids.get(i));           
                             }             
                        in.close();
     
                       }
                    }
                }catch(Exception e){              
                       }           
                 //closes the print writer
                    out.flush();
                out.close();
            }
    }

  12. #11
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    Default Re: I/O Help with Collections/Ordering?

    Compare the input file to the output and find the pattern to see what the code is doing

  13. #12
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    Default Re: I/O Help with Collections/Ordering?

    I appreciate you guys helping me understand this, and I apologize for my slow learning here, I will get this eventually!

    So in that code I have what I need, however I have way more than I want as well.... I guess I figured I needed to pull from the list to get it sorted the way I need it, as when I just print idnums I get the same issue. They will print but not sorted

    --- Update ---

    Got it, I see that it is printing essentially (1), (1,2), (1,2,3) etc.. but I am not sure how to just tell it to print the last read through

  14. #13
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    Default Re: I/O Help with Collections/Ordering?

    Quote Originally Posted by BTaggar View Post
    Got it, I see that it is printing essentially (1), (1,2), (1,2,3) etc.. but I am not sure how to just tell it to print the last read through
    110001
    110001, 110223
    110001, 110020, 110223
    110001 ,110020, 110223, 110333
    110001, 110020, 110223, 110333, 110442
    110001, 110020, 110223, 110333, 110421, 110442
    110001, 110020, 110223, 110333, 110421, 110442, 112352
    Pay very close attention to what it is doing. Follow the code line by line.
    Get a value. Add the value to the list. Sort the list. Output the list.
    Get next value. Add value. Sort list. Output list.
    Get next value. Add value. Sort list. Output list.
    ~etc

    Some of those things do not need to be done every iteration of the loop, but only once after all of the data is in the list

    Post the new version of the code so we can see the overall picture again, Junky brought up some points that should be tended to

  15. The Following User Says Thank You to jps For This Useful Post:

    BTaggar (August 27th, 2013)

  16. #14
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    Default Re: I/O Help with Collections/Ordering?

     
    /*
     * To change this template, choose Tools | Templates
     * and open the template in the editor.
     */
    package kettask2pt2;
     
    import java.util.Scanner;
    import java.io.BufferedReader;
    import java.io.FileNotFoundException;
    import java.io.IOException;
    import java.io.PrintWriter;
    import java.io.FileReader;
    import java.io.File;
    import java.util.ArrayList;
    import java.util.*;
    /**
     *
     * @author Brandon
     */
     
    public class KETTask2Pt2{
       public static void main(String[] args) throws FileNotFoundException, IOException
        {
     
          // Ask for the file name listings.txt
     
            Scanner inputscan = new Scanner(System.in);
            System.out.print("Please enter listings.txt: ");
            String inputFile = inputscan.next();
     
          // Creates variables & BufferedWriters
            String line = null ;
            PrintWriter out = new PrintWriter("overview.txt");
            File input = new File(inputFile);
            BufferedReader in = new BufferedReader(new FileReader(input));   
            int count = 0;
            double sum = 0;
     
          // Totals and adds properties listed and the values of the properties  
      while ((line = in.readLine())!= null)     
                {
                count++;
                String[] thelist = line.split("[\\s}]");
                Double totalvalue = Double.parseDouble(thelist[2]);
     
    	       {
                    sum+=totalvalue;
                   }        
                }
                out.println("Total properties listed:  " + count);
                out.println("Total value of properties listed: " + "$" +sum + "0" +"\n");
                in.close();
     
         //Adds the id numbers for the individual listings              
          try {
                 ArrayList<String> ids = new ArrayList<String>();                     
                 Scanner idscan = new Scanner((input)); 
     
              while (idscan.hasNextLine())
     
     
     
               {              
                 line = idscan.nextLine();
                 String[] fields = line.split("[\\s}]");
                 String idnums = (fields [0]);  
                 ids.add(idnums);
                  Collections.sort(ids);
                       {
     
                        int arraysize = ids.size();
                             for(int i=0; i<arraysize; i++){
                           out.println(ids.get(i));           
                             }             
                        in.close();
     
                       }
                    }
                }catch(Exception e){              
                       }           
                 //closes the print writer
                    out.flush();
                out.close();
            }
    }
    }


    --- Update ---

    Here is where I am at right now and the results I am getting

    Total properties listed: 7
    Total value of properties listed: $2120000.00

    110001
    110001
    110223
    110001
    110020
    110223
    110001
    110020
    110223
    110333
    110001
    110020
    110223
    110333
    110442
    110001
    110020
    110223
    110333
    110421
    110442
    110001
    110020
    110223
    110333
    110421
    110442
    112352

    --- Update ---

    I feel like I am getting closer, but still struggling with why it is reading it so many times and creating those duplicates

    --- Update ---

    Sorry I posted the wrong code before..

    --- Update ---

    It took me a while, but I finally got there! Thank you all for your help! Here is my final code:

    /*
     * To change this template, choose Tools | Templates
     * and open the template in the editor.
     */
    package kettask2pt2;
     
    import java.util.Scanner;
    import java.io.BufferedReader;
    import java.io.FileNotFoundException;
    import java.io.IOException;
    import java.io.PrintWriter;
    import java.io.FileReader;
    import java.io.File;
    import java.util.ArrayList;
    import java.util.*;
    /**
     *
     * @author Brandon
     */
     
    public class KETTask2Pt2{
       public static void main(String[] args) throws FileNotFoundException, IOException
        {
     
          // Ask for the file name listings.txt
     
            Scanner inputscan = new Scanner(System.in);
            System.out.print("Please enter listings.txt: ");
            String inputFile = inputscan.next();
     
          // Creates variables & BufferedWriters
            String line = null ;
            PrintWriter out = new PrintWriter("overview.txt");
            File input = new File(inputFile);
            BufferedReader in = new BufferedReader(new FileReader(input));   
            int count = 0;
            double sum = 0;
            ArrayList<String> ids = new ArrayList<String>(); 
          // Totals and adds properties listed and the values of the properties  
      while ((line = in.readLine())!= null)     
                {
                    String[] fields = line.split("[\\s}]");
                    ids.add(fields[0]);
                    String idnums = (fields [0]); 
                count++;
                String[] thelist = line.split("[\\s}]");
                Double totalvalue = Double.parseDouble(thelist[2]);
     
    	       {
                    sum+=totalvalue;
                   }        
                }
                out.println("Total properties listed:  " + count);
                out.println("Total value of properties listed: " + "$" +sum + "0" +"\n");
                in.close();
     
         //Adds the id numbers for the individual listings              
          try {                                                                                
                  Collections.sort(ids);            
                             {
                       {
                        for(Object propertyNumber : ids)
                        out.println(propertyNumber);
     
                             }             
                        in.close(); 
                       }
     
                }catch(Exception e){              
                       }           
                 //closes the print writer
                    out.flush();
                out.close();
            }
    }

  17. #15
    Super Moderator jps's Avatar
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    Default Re: I/O Help with Collections/Ordering?

    What does idnums do?
    inputscan is never closed.

    --- Update ---

    String[] fields = line.split("[\\s}]");
    String[] thelist = line.split("[\\s}]");
    No need to parse the string twice

  18. The Following User Says Thank You to jps For This Useful Post:

    BTaggar (August 27th, 2013)

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