Question

I am trying to display statistics from a simple text file using arrays in Java. I know what I am supposed to do, but I don’t really how how to code it. So can anybody show me a sample code on how to do it.

So let’s say the text file is called gameranking.txt, that contains the following information (This is a simple txt file to use as an example):

Game Event, 1st place, second place, third place, fourth place
World of Warcraft, John, Michael, Bill, Chris
Call of Duty, Michael, Chris, John, Bill
League of Legends, John, Chris, Bill, Michael. 

My goal is to display stats such as how many first places, second places.. each individual won in a table like the following

Placement     First place, second, third, fourth
John            2            0       1      0
Chris           0            2       0      1
etc...       

My thought:
First, I would read the gameranking.txt and stores it to “input”. Then I can use the while loop to read each line and store each line into a string called “line”, afterward, I would use the array method “split” to pull out each string and store them into individual array. Afterward, I would count which placement each individual won and display them into a neat table using printf.

My first problem is I don’t know how to create the arrays for this data. Do I first need to read through the file and see how many strings are in each row and column, then create the array table accordingly? Or can I store each string in an array as I read them?

The pseudocode that I have right now is the following.

• Count how many rows are there and store it in row
• Count how many column are there and store it in column
• Create an array
• String [] [] gameranking = new String [row] [column]
• Next read the text file and store the info into the arrays

using:

while (input.hasNextLine) {
    String line = input.nextLine();
    while (line.hasNext()) {
        Use line.split to pull out each string
        first string = event and store it into the array
        second string = first place
        third string =......

• Somewhere in the code, I need to count the placement….

Can somebody please show me how I should go about doing this?

Answer 1

I am not going to write the full program, but I will try to tackle each question and give you a simple suggestion:

Reading the initial file, you can get each line and store it in a string using a BufferedReader (or if you like, use a LineNumberReader)

BufferedReader br = new BufferedReader(new FileReader(file));
String strLine;
while ((strLine = br.readLine()) != null)   {
......Do stuff....
}

At that point, in the while loop you will go through the string (since it comma delimited, you can use that to seperate each section). for each substring you can
a) compare it with first, second, third, fourth to get placement.
b) if its not any of those, then it could either be a game name or a user name

You can figure that out by position or nth substring (ie if this is the 5th substring, its likely to be the first game name. since you have 4 players, the next game name will be the 10th substring, etc.). Do note, I ignored “Game event” as that’s not part of the pattern. You can use split to do this or a number of other options, rather than try to explain that I will give you a link to a tutorial I found:
http://pages.cs.wisc.edu/~hasti/cs302/examples/Parsing/parseString.html

As for tabulating results, Basically you can get an int array for each player which keeps track of their 1st, 2nd, 3rd, awards etc.

int[] Bob = new int[4]; //where 0 denotes # of 1st awards, etc.
int[] Jane = new int[4]; //where 0 denotes # of 1st awards, etc.

Showing the table is a matter of organizing the data and using a JTable in a GUI:
http://docs.oracle.com/javase/tutorial/uiswing/components/table.html

Alrighty…Here is what I wrote up, I am sure there is a cleaner and faster way, but this should give you an idea:

String[] Contestants = {"Bob","Bill","Chris","John","Michael"};

int[][] contPlace=new int[Contestants.length][4];
String file = "test.txt";

public FileParsing() throws Exception {
    Arrays.fill(contPlace[0], 0);
    Arrays.fill(contPlace[1], 0);
    Arrays.fill(contPlace[2], 0);
    Arrays.fill(contPlace[3], 0);
    BufferedReader br = new BufferedReader(new FileReader(file));
    String strLine;
    while((strLine=br.readLine())!=null){
        String[] line = strLine.split(",");
        System.out.println(line[0]+"/"+line[1]+"/"+line[2]+"/"+line[3]+"/"+line[4]);
        if(line[0].equals("Game Event")){
            //line[1]==1st place;
            //line[2]==2nd place;
            //line[3]==3rd place;
        }else{//we know we are on a game line, so we can just pick the names
            for(int i=0;i<line.length;i++){
                for(int j=0;j<Contestants.length;j++){
                    if(line[i].trim().equals(Contestants[j])){
                        System.out.println("j="+j+"i="+i+Contestants[j]);
                        contPlace[j][i-1]++; //i-1 because 1st substring is the game name
                    }

                }
            }
        }
    }
    //Now how to get contestants out of the 2d array
    System.out.println("Placement  First Second Third Fourth");
    System.out.println(Contestants[0]+" "+contPlace[0][0]+" "+contPlace[0][1]+" "+contPlace[0][2]+" "+contPlace[0][3]);
    System.out.println(Contestants[1]+" "+contPlace[1][0]+" "+contPlace[1][1]+" "+contPlace[1][2]+" "+contPlace[1][3]);
    System.out.println(Contestants[2]+" "+contPlace[2][0]+" "+contPlace[2][1]+" "+contPlace[2][2]+" "+contPlace[2][3]);
    System.out.println(Contestants[3]+" "+contPlace[3][0]+" "+contPlace[3][1]+" "+contPlace[3][2]+" "+contPlace[3][3]);
    System.out.println(Contestants[4]+" "+contPlace[4][0]+" "+contPlace[4][1]+" "+contPlace[4][2]+" "+contPlace[4][3]);

}

If you need to populate the contestants array or keep track of the games, you will have to insert appropriate code. Also note, using this 2-d array method is probably not best if you want to do anything other than display them. You should be able to take my code, add a main, and see it run.