Skip first line while reading CSV file in Java

Question

I am writing a parser code to read a .csv file and parse it to XML. This is the code I have and it works, except I would like it to skip the first line in the file. So I decided to set up a HashMap but it doesn't seem to work:

for (int i = 0; i < listOfFiles.length; i++) {
        File file = listOfFiles[i];
        if (file.isFile() && file.getName().endsWith(".csv")){
        
            System.out.println("File Found: " + file.getName());//Prints the name of the csv file found

            String filePath = sourcepath + "\\" + file.getName();

            BufferedReader br = new BufferedReader(new FileReader(file));  


String line;
int n = 1;
Map<Integer,String> lineMap = new HashMap<Integer,String>();
int k=2;
while ((line = br.readLine()) != null) {
    System.out.println(n + " iteration(s) of 1st While Loop");
    
                    lineMap.put(k, line);

    fw.write("          <ASSET action=\"AddChange\">\n");
    fw.write("              <HOSTNAME>\n");
    hostName=line.substring(0, line.indexOf(","));
    fw.append(hostName);
    fw.write("</HOSTNAME>\n");
    fw.write("              <HOSTID>\n");
    hostID=line.substring(line.indexOf(",")+1, nthOccurrence(line, ',', 1));
    fw.append(hostID);
    fw.write("</HOSTID>\n");
    fw.write("              <MACMODEL>\n");
    machineModel=line.substring(nthOccurrence(line, ',', 1)+1, nthOccurrence(line, ',', 2));
    fw.append(machineModel);
    fw.write("</MACMODEL>\n");
    fw.write("              <PROMODEL>\n");
    processorModel=line.substring(nthOccurrence(line, ',', 2)+1, nthOccurrence(line, ',', 3));
    fw.append(processorModel);
    fw.write("</PROMODEL>\n");
    fw.write("              <CORE>\n");
    core=line.substring(nthOccurrence(line, ',', 3)+1, nthOccurrence(line, ',', 4));
    fw.append(core);
    fw.write("</CORE>\n");
    fw.write("              <PROC>\n");
    proc=line.substring(nthOccurrence(line, ',', 4)+1, nthOccurrence(line, ',', 5));
    fw.append(proc);
    fw.write("</PROC>\n");
    fw.write("              <TIER>\n");
    tier=line.substring(nthOccurrence(line, ',', 5)+1, nthOccurrence(line, ',', 6));
    fw.append(tier);
    fw.write("</TIER>\n");
    fw.write("              <PRODNAME>\n");
    productName=line.substring(nthOccurrence(line, ',', 6)+1, nthOccurrence(line, ',', 7));
    fw.append(productName);
    fw.write("</PRODNAME>\n");
    fw.write("              <VERSION>\n");
    version=line.substring(nthOccurrence(line, ',', 7)+1, nthOccurrence(line, ',', 8));
    fw.append(version);
    fw.write("</VERSION>\n");
    fw.write("              <SCRIPTDATA>\n");
    scriptData=line.substring(nthOccurrence(line, ',', 8)+1, line.length());
    fw.append(scriptData);
    fw.write("</SCRIPTDATA>\n");
    

  fw.write("            </ASSET>\n");
  k++;
}n++;

This is a snippet of the main part of the code. Any Ideas or Solutions???

Not your down-voter, but clarify your "it does seem to work", please. — Hovercraft Full Of Eels
– Hovercraft Full Of Eels, Commented Aug 19, 2013 at 4:16
We know that, but in the future, tell more about how it doesn't work. The more useful information you give, the easier it will be to answer your questions. — Hovercraft Full Of Eels
– Hovercraft Full Of Eels, Commented Aug 19, 2013 at 4:30

David Maust · Accepted Answer · 2013-08-19 04:18:58Z

33

You might consider placing headerLine = br.readLine() before your while loop so you consume the header separately from the rest of the file. Also you might consider using opencsv for csv parsing as it may simplify your logic.

answered Aug 19, 2013 at 4:18

David Maust

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Comments

n4rzul · Accepted Answer · 2016-02-24 12:27:08Z

15

I feel compelled to add a java 8 flavored answer.

List<String> xmlLines = new BufferedReader(new FileReader(csvFile))
    .lines()
    .skip(1) //Skips the first n lines, in this case 1      
    .map(s -> {
        //csv line parsing and xml logic here
        //...
        return xmlString;
    })
    .collect(Collectors.toList());

answered Feb 24, 2016 at 12:27

n4rzul

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Comments

Paulo Almeida · Accepted Answer · 2014-08-28 16:22:15Z

7

Create a variable interation and initialize with 0. Check it as very first thing in while loop.

String line;
int iteration = 0;
while ((line = br.readLine()) != null) {
    if(iteration == 0) {
        iteration++;  
        continue;
    }
    ...
    ...
}

edited Aug 28, 2014 at 16:22

Paulo Almeida

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answered Aug 19, 2013 at 4:16

Azodious

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2 Comments

Kala J Over a year ago

What if I wanted to skip the first two lines? one line with text and the next line is an empty row/whitespace?

user1438038 Over a year ago

@KalaJ: Do if(iteration == 0 || iteration == 1) instead or even better if(iteration < 2). Got it?

Scary Wombat · Accepted Answer · 2013-08-19 04:17:25Z

2

I am rather confused by your code, your have the lineMap and you also have fw (whatever that is). Which one are you using? You say you want to skip the first line, but you don't

if (firstLine == true) {
   firstLine = false;
   continue;
}

I would also suggest using a library like CSVReader which I belive even has a property ignoreFirstLine

http://opencsv.sourceforge.net/apidocs/au/com/bytecode/opencsv/CSVReader.html

answered Aug 19, 2013 at 4:17

Scary Wombat

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Comments

achakravarty · Accepted Answer · 2013-08-19 04:18:28Z

2

why don't you just use the for loop

for(int i=1; (line = br.readLine()) != null; i++)
{
    //Your code
}

answered Aug 19, 2013 at 4:18

achakravarty

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1 Comment

SudhirKumar Over a year ago

How initializing i=1 will read from second line, there is no control on a variable i, using i is obsolete here.

0xMinCha · Accepted Answer · 2021-06-10 21:35:34Z

2

An easy technique, declare a variable and assign it a value (e.g. int k = 0;), and increment the variable value right after you enter into the loop. The code is given below.

BufferedReader csvReader = new BufferedReader(new FileReader("mycsv.csv"));
        // declare a variable
        int k=0;
        while ((row = csvReader.readLine()) != null) {
            if(k == 0){
                k++;
                continue;
            }
         //rest of your code 
         // inside while loop
        }

answered Jun 10, 2021 at 21:35

0xMinCha

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Comments

mishik · Accepted Answer · 2014-03-14 07:53:39Z

0

Use buffer reader two times, like this:

while ((line = br.readLine()) != null) {
  while ((line = br.readLine()) != null) {
    //your code                     
  }
}

edited Mar 14, 2014 at 7:53

mishik

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answered Mar 14, 2014 at 7:33

user3418885

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Comments

rahulpatil · Accepted Answer · 2016-12-03 04:38:39Z

0

boolean isRecord = false;
for (CSVRecord record : records) {
    if(isRecord){
        //process records here.
    }else{
        isRecord = true;
    }
}

Instead of adding counter adding flag will not hit the performance.

answered Dec 3, 2016 at 4:38

rahulpatil

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Comments

Michael Cropper · Accepted Answer · 2022-06-02 13:32:07Z

0

A simple solution, read the first line outside of the loop

        String[] nextLine;
        String[] headerLineInCSVFile = csvReader.readNext();
        while ((nextLine = csvReader.readNext()) != null) {
            String columnOne = nextLine[0];
        }

answered Jun 2, 2022 at 13:32

Michael Cropper

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Comments

user3585491 · Accepted Answer · 2014-09-05 06:37:33Z

-1

For skipping first line(which normally contains header of the columns) take a variable and increase this variable in while loop at first place, and continue;

int lineNumber = 0;

and then in while loop 

while ((line = br.readLine()) != null) {
                        if(lineNumber == 0) {
                            lineNumber++;
                            continue;
                        }
                        lineNumber++;

                       //do waterver u have to do with the tokens in this line(second line)

            }

answered Sep 5, 2014 at 6:37

user3585491

1

1 Comment

Andrew Barber Over a year ago

The same basic answer was posted more than a year ago.

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