Thread: I/O Help with Collections/Ordering?

What does the file look like?

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

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!

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?

What happened when you tried?

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();
        }
}

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

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

Originally Posted by BTaggar

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

 
/*
 * 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();
        }
}

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