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How to move the specific column in CSV to first column using java

Posted on 2009-05-12
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Last Modified: 2013-11-13
Hi I want to move the specific column with values to the first column in CSV. will it be possible using java code
ex:
COLUMN1 COLUMN2 COLUMN3
a1             b1              c1
a2             b2              c2
a2             b3              c3

and i want to be
if(col[i].equals("COLUMN3"))

COLUMN3 COLUMN2 COLUMN3
c1             b1             a1
c2             b2             a2
c3            b3              a3


I am using following code to read csv

BufferedReader csvReader;
            csvReader = new BufferedReader(new
                    FileReader(csvFileName));
            int fieldCount = 0;
            String[] csvFields = null;
            StringTokenizer stringTokenizer = null;
 
String curLine = csvReader.readLine();
            if(curLine != null)
            {
                stringTokenizer = new StringTokenizer(curLine, ",");
                fieldCount = stringTokenizer.countTokens();
                if(fieldCount > 0)
                {
                    csvFields = new String[fieldCount];
                    int i=0;
                    while(stringTokenizer.hasMoreElements()){
                        csvFields[i++] =
                                String.valueOf(stringTokenizer.nextElement());
             
                    }
                }
            }
            
            for(int i=0;i<csvFields.length;i++){
            	String csvField=csvFields[i].toUpperCase();
            	csvFields[i]=csvField.replaceAll(" ","_");
            	if(csvFields[i].equals("ETHNIC_ORIGIN")){
            		
            	}
            	
            }
 
            while((curLine = csvReader.readLine()) != null)
            {
            	String strArr[] = curLine.split(",");
            	String result ="";
            	 String temp ="";
            	for ( int i =0 ;i<strArr.length;i++)
            	{
            	  if( strArr[i].equals(""))
            	    temp = "(Blanks),";
            	 else
            	    temp = strArr[i] + ",";
            	result = result +  temp;
            	}
            	
            	curLine=result;
            	
            	int pp = 0;
            	  while (true) {
            	    int found = curLine.indexOf("\"", pp);
            	    if (found == -1) break;
            	    int start = found + 1; // start of actual quote
            	    int end = curLine.indexOf("\"", start);
            	    
            	    String str1=curLine.substring(start, end);
            	    str1=str1.replaceAll(",","");
            	    String str2="";
            	    str2=curLine.substring(end+1, curLine.length());
            	    
            	    if(found!=0){
            	    	curLine=curLine.substring(0, start-1)+str1+str2;
            	    	
            	    }
            	    else{
            	     	curLine=str1+str2;
            	        
            	    }
            	    pp = end + 1;  // advance i to start the next iteration
            	  }
				
                stringTokenizer = new StringTokenizer(curLine, ",");
------

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Question by:ramadevimandala
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7 Comments
 
LVL 86

Expert Comment

by:CEHJ
ID: 24363381
I would use a proper CSV api such as Ostermiller but all you need to do is to swap the columns in the array
0
 
LVL 86

Expert Comment

by:CEHJ
ID: 24363389

String temp = array[2];
array[2] = array[0];
array[0] = temp;

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LVL 92

Accepted Solution

by:
objects earned 500 total points
ID: 24370281
simplest would be to use a loop to switch the columns once it is read
another option would be too use a Map for your columns making them easily accessible
depends on your requirements

let me know if you need help with it

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Author Comment

by:ramadevimandala
ID: 24372010
Hi,
Thank you for ur help , I am trying to loop thru columns and swapping the values, let me try once this
0
 
LVL 92

Expert Comment

by:objects
ID: 24372033
no worries, should be around for a few hours of you get stuck

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Author Comment

by:ramadevimandala
ID: 24429408
swaping the elements in loop is working fine.. thanks
0
 
LVL 86

Expert Comment

by:CEHJ
ID: 24429433
ramadevimand, that's good. Can you post the code you're now using?
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