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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

0
 

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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