CODEWITHSUNDEEP
javaarrays2d
Pascal Gernhardt
Pascal Gernhardt

Reputation: 3

Convert text to 2d array

Im trying to fill a 2d-array with a text file.

My text file looks like this:

#######
# .# @#
#  #  #
#$##$##
#  #  #
#     #
#######

Its basicaly a level for a game. My final 2d-array shall look like this:

char [][] a = new char [6][6];

a[0][0] = #; a[0][1] = #; ... a[0][6] = #;
a[1][0] = #; a[1][1] =  ; a[1][2] = . ; ... a[1][6] = #;
.
.
.
a[6][0] = #;        . . .     a[6][6] = #;

My attempt is to read the rows in, convert them to 1d arrays and fill the 2d array with 2 loops. Then i need to print them out.

public class pp {

public static void main (String[] args) {

char [][]array2d = new char [6][7];

In.open("Level2.txt");

    while (In.done()){

        for (int rows=0; rows<7; rows++){

            String string = In.readLine();
            char [] array1d = string.toCharArray();

                for(int columns=0; columns<7;columns++){

                    array2d [rows][columns] = array1d [columns];
                    Out.print(array2d[rows][columns]);  

                    }                                       

            Out.println(); 

        }

    }

In.close();}}

Bizarrely it only prints everything out when i set the columns to 7 

char [][]a = new char [6][7];

and the rows to 6 

 for (int rows=0; rows<6; rows++){

I also become the error:
Exception in thread "main" java.lang.ArrayIndexOutofBoundException:0 at pp.main(pp.java:18)

thats here

array2d [rows][columns] = array1d [columns];

And i am also not able to print the array2d out (code not shown). It simply does nothing when i try to get a[6][0] for example.

Im literally searching and trying for hours, i hope you can help me.

Upvotes: 0

Views: 1181

Answers (2)

eighthrazz
eighthrazz

Reputation: 331

Java 8 Streams make it really easy to create a two-dimensional character array from a text file.

char[][] array2d = Files.lines(file.toPath())
    .map(String::toCharArray)
    .toArray(char[][]::new);

One difference being your text file will determine the size of the two-dimensional character array.

Upvotes: 1

khancock
khancock

Reputation: 147

You can also dramatically reduce your code to not need so many for loops by realizing that when you call 

In.readLine();

you are taking in a string which you correctly turn into a char array. But you could set that directly into your array. Which as the comments above have stated is not instantiated correctly. You have 7 columns and 7 rows, thus you need 

new char[7][7]

But when you call say the first element counting always STARTS AT 0. So char[0][0] would output the first element

For example 

public class HelloWorld
{
  public static void main(String[] args)
  {
    char[][] x = new char[7][7];
    char[] h = "Helpers".toCharArray();
    x[0] = h;
    for (char c : x[0]) System.out.println(c);
   }
}

So in this example I set my first row in my 2D array equal to an entire list. So from here its pretty easy to find a full solution to your problem without having to use so many lines of code.

Upvotes: 0

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