Read Tab Delimited file into ArrayList<ArrayList> in Java

Question

I am looking for a way to read a tab delimited file of baseball stats into a two dimensional arraylist. I'm using a scanner to read the file, but I can't think of how to read just one line into an array list, stopping at the line break, then read the next line into the next arraylist.

This is my first time trying to create a multidimensional arraylist, and I thought it would be much the same as reading multidimensional arrays. I was clearly mistaken.

    public static ArrayList dataRead(String fileloc) throws FileNotFoundException {
    ArrayList array = new ArrayList<ArrayList>();
    Scanner s = new Scanner(new File(fileloc)).useDelimiter("\t");
    ArrayList<String> rows = new ArrayList<String>();
    ArrayList cols = new ArrayList();
    while(s.nextLine() != null) {
        cols.add(s.next());
    }
    return array;
}

This is my code as of now. Would it be a better choice to read each line into a string, delimited by returns, then read each string into an appropriate arraylist?

Please show us what you have so far. Also, read the faq and How to Ask for guidelines on how to ask questions here. — Jim Garrison
– Jim Garrison, Commented Apr 4, 2012 at 18:26
What are you having trouble with reading the line or creating the array from that line? — twain249
– twain249, Commented Apr 4, 2012 at 18:26

Amir Afghani · Accepted Answer · 2012-04-04 18:35:49Z

4

You could use opencsv and set the delimeter to tab. Check out the examples on the link I provided.

CSVReader reader = new CSVReader(new FileReader("yourfile.csv"), '\t');
String [] nextLine;
while ((nextLine = reader.readNext()) != null) {
    // nextLine[] is an array of values from the line
    System.out.println(nextLine[0] + nextLine[1] + "etc...");
}

Although it's not clear from your question what your actual issue is when trying to 'roll your own'

edited Apr 4, 2012 at 18:35

answered Apr 4, 2012 at 18:25

Amir Afghani

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Comments

Reid Mac · Accepted Answer · 2012-04-04 18:30:14Z

1

I'm not sure what the stats look like, but it might be better to use a HashMap which has Key/value pairs instead, but I could be wrong. I don't know what your dataset looks like.

For a start, you can delimit the lines by using the "\t" escape character. For Example:

Scanner s = new Scanner(input).useDelimiter("\t");

Then you can loop through the results and for every pair add it to the map.

answered Apr 4, 2012 at 18:30

Reid Mac

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1 Comment

gelliott181 Over a year ago

If I could hashmap, I would, but I was specifically told arraylist. The useDelimiter was a big part of what I was forgetting, thanks for bringing it up!

eabraham · Accepted Answer · 2012-04-04 18:47:10Z

1

I think you need to rethink your data structure to something more conducive to what you are trying to store. I would recommend that you create a player object and store that into an arraylist.

public class Player{
    double battavg;
    String name;
    //add more values like rbi, etc.
    public Player(name,battavg){
        this.name=name;
        this.battavg=battavg;
    }
    public String getName(){
        return name;
    }
    public String getBattAvg(){
        return battavg;
    }
    public setBattAvg(double battavg){
        this.battavg=battavg;
    }
    public setName(String name){
        this.name=name;
    }
}

public class baseball{
    public static void main(String[] args){
        ArrayList<Player> list = new ArrayList<Player>();
        //read in values from csv
        list.add(new Player(name,battavg));
    }
}

answered Apr 4, 2012 at 18:47

eabraham

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1 Comment

gelliott181 Over a year ago

That's a really good idea. I kinda feel dumb for not thinking of keeping each player in an object. That also makes is much easier to work with. Thanks for the help.

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