How to read in a file and change the column attributes

Question

Hi,
I'm new to java and i'm stuggling to find a way to read in a text file and perform calculations on the data, such as to normalise it.
What in want to do is normalise the data by finding the greatest value in a column and then divide all the other values in the column with that value.
I know how to read a file in and store each line in a vector but for this problem i think i need to store each column in an array, but i'm not sure how to do this.
Can anyone help please?
Thanks

Answer 1

Hi,
I'm new to java and i'm stuggling to find a way to
read in a text file and perform calculations on the
data, such as to normalise it.
What in want to do is normalise the data by finding
the greatest value in a column and then divide all
the other values in the column with that value.
I know how to read a file in and store each line in a
vector but for this problem i think i need to store
each column in an array, but i'm not sure how to do
this.
Can anyone help please?
ThanksI think this should work but I wrote it out without completely thinking about it (hopefully to get things started).
So if you had this:
age height earnings
0 2 100
1 3 50
2 1 0
For the age column you'd take 2 as the largest and then divide 0 and 1 by two to get 0, .5.
First build up test files that seperate the columns in different ways. With spaces, tabs, and the ASCI Control character for null ( I think it's 0 ). Your program should detect
numbers and spaces, tabs control character, commas and periods (for money). Because numbers don't have spaces it should be easy to keep track of which column
you're in.
Store each line into a 3D String array with each index containing a String built up from the chars scanned in on each line, when a blank area is found followed by another
number iterate the column index. When you come to the end of the line set column == 0 and row+1.
private String[][][] test = new String[2][6][1];
20     3      11      14      44       0
4      5       7      80      91      49
test[0][0][0] would be row 1 col 1 value 1 ((20))
test[0][1][0] would be r1, c2, v1 ((3))
test[1][0][0] would be r2, c1, v1 ((4))
test[1][2][0] would be r2, c3, v1 ((7))
test[1][5][0] would be r2, c6, v1 ((49))
package source.Final;
import javax.swing.*;
import java.io.*;
public class S7
     public static void main(String[] args)
          getContents();
          System.exit(0);
     public static void getContents()
          String lineSep = System.getProperty("line.separator");
          char c = ' ';
          int iterator = 0;
          int i = 0;
          int charNum = 1;
          int lineCount = 1;
         //declared here only to make visible to finally clause
         BufferedReader input = null;
         BufferedWriter out = null;
         try {
                     String line = null;
                      * This implementation reads / writes one line at a time
                      * using the buffered reader / writer Java classes.
                     input = new BufferedReader( new FileReader( "C:\\Scan file test\\Read\\test1.txt" ));
                       out = new BufferedWriter( new FileWriter( "C:\\Scan file test\\Read\\test2.txt" ));
                     //input = new BufferedReader( new FileReader( "C:\\Scan file test\\Read\\booked_policies1.txt" ));
                       //out = new BufferedWriter( new FileWriter( "C:\\Scan file test\\Write\\booked_policies1.txt" ));
                     //input = new BufferedReader( new FileReader( "C:\\Scan file test\\Read\\booked_policies2.txt" ));
                       //out = new BufferedWriter( new FileWriter( "C:\\Scan file test\\Write\\booked_policies2.txt" ));
                     //input = new BufferedReader( new FileReader( "C:\\Scan file test\\Read\\booked_policies3.txt" ));
                       //out = new BufferedWriter( new FileWriter( "C:\\Scan file test\\Write\\booked_policies3.txt" ));
                     out.write( "Character\tLine Number\tCharacter Number\tAscii Value" + lineSep );                     
                          while (( line = input.readLine()) != null)
                          i = 0;
                          charNum = 1;
                          iterator = 0;
                          while( i < line.length() )
                                           c = line.charAt(iterator);                                             
                                        if( (int)c == 0 || (int)c == 9 )
                                             break;
                                        else if( c >= '[' && c <= '_')
                                             {out.write( "["+c+"]\t\t"+"["+lineCount+"]\t\t"+"["+charNum+"]\t\t\t"+"["+(int)(c)+"]"+lineSep );}
                                        else if( c <  ' ' )// && (int)c != 0 && (int)c != 9  )
                                             {out.write( "["+c+"]\t\t"+"["+lineCount+"]\t\t"+"["+charNum+"]\t\t\t"+"["+(int)(c)+"]"+lineSep );}
                                        else if( c >  ';' && c <= '@' && c != '=')
                                             {out.write( "["+c+"]\t\t"+"["+lineCount+"]\t\t"+"["+charNum+"]\t\t\t"+"["+(int)(c)+"]"+lineSep );}
                                        else if( c >= '!' && c < '"' )
                                             {out.write( "["+c+"]\t\t"+"["+lineCount+"]\t\t"+"["+charNum+"]\t\t\t"+"["+(int)(c)+"]"+lineSep );}
                                        else if( c >  'z' && c < '~' )
                                             {out.write( "["+c+"]\t\t"+"["+lineCount+"]\t\t"+"["+charNum+"]\t\t\t"+"["+(int)(c)+"]"+lineSep );}
                                        else if( c == '%' )
                                             {out.write( "["+c+"]\t\t"+"["+lineCount+"]\t\t"+"["+charNum+"]\t\t\t"+"["+(int)(c)+"]"+lineSep );}
                                        else if( c >  '~' )
                                             {out.write( "["+c+"]\t\t"+"["+lineCount+"]\t\t"+"["+charNum+"]\t\t\t"+"["+(int)(c)+"]"+lineSep );}
                                        charNum += 1;
                                           iterator += 1;
                                           i++;
                                lineCount += 1;
         catch (FileNotFoundException ex) {ex.printStackTrace();     System.out.println("File not found.");}
             catch (IOException ex){ex.printStackTrace();               System.out.println("IO Error.");}
         finally{ try{ if( input != null ) input.close();                if( out != null ) out.close();}
                catch (IOException ex){ex.printStackTrace();        System.out.println("IO Error #2.");}
    }