读取文件并将其转换为Java中的二维数组

Question

I need to make a 20x45 array using a text file. For example using a 3*5 array:

Text input from file:
Four score and seven years ago

The array (Using _ to indicate spaces):
F our _
score
_ and _

I'll be transparent in saying I'm pretty much brand new to Java and I've been trying for a while and don't know where to begin. I have gotten this code so far:

    // Create file instance.
    java.io.File file = new java.io.File("array.txt"); 

    int totalRow = 20;
    int totalColumn = 45;
    char[][] myArray = new char[totalRow][totalColumn];
    Scanner scanner = new Scanner(file);

    for (int row = 0; scanner.hasNextLine() && row < totalRow; row++) {    
        char[] chars = scanner.nextLine().toCharArray();
        for (int i = 0; i < totalColumn && i < chars.length; i++) {
            myArray[row][i] = chars[i];
            System.out.println(myArray[row][i]);
        }
        //System.out.println("");
    }

I have tried many different iterations and I'm stuck.
Thanks in advance.

Answer 1

The problem is that the first time scanner.nextLine().toCharArray(); is ran, it reads the entire text because the file contains only one line. However, in that loop your code only process the first row of the 2d array.

for (int row = 0; scanner.hasNextLine() && row < totalRow; row++) {    
    char[] chars = scanner.nextLine().toCharArray(); //Notice this reads the entire text the first loop when row=0
    for (int i = 0; i < totalColumn && i < chars.length; i++) {
        //This loop fills the first row of the array when row=0
        myArray[row][i] = chars[i];
        System.out.println(myArray[row][i]);
    }
    //End of loop, the next time scanner.hasNextLine() returns false and loop terminates
}

To solve this problem, you should read chars outside of the loop (read it only once). Then use a single index to iterate through the chars while iterating through the 2d array.

char[] chars = scanner.nextLine().toCharArray();
int i = 0;

for (int row = 0; row < totalRow & i<chars.length; row++) {    
   for (int col = 0; col < totalColumn & i<char.length; col++) {
       myArray[row][col] = chars[i];
       i++;
   }
}