The 8.1.5 exercise usually focuses on iterating through a 2D array and applying specific logic to change its contents. Here is a comprehensive guide to mastering these manipulations. The Foundation: The Nested Loop
Always ensure your loop termination conditions use < matrix.length and < matrix[row].length . Using <= will cause a runtime crash.
// Task 3: Write a function that swaps the first and last row function swapFirstLastRow(matrix) // Your code here Codehs 8.1.5 Manipulating 2d Arrays
💡 It is very common to swap the row and column variables. Always use the format array[row][column] .
Suppose you want to create a 3x3 grid of buttons, where each button has a unique value. You can use a 2D array to represent the grid and manipulate it to add or remove buttons. Always use the format array[row][column]
Imagine a spreadsheet, a chess board, or a tic-tac-toe grid. These are all perfect real-world representations of 2D arrays. While a standard array stores elements in a single row, a 2D array stores elements in and columns .
[0,0] [0,1] [0,2] <-- Row 0 [1,0] [1,1] [1,2] <-- Row 1 [2,0] [2,1] [2,2] <-- Row 2 Imagine a spreadsheet, a chess board, or a tic-tac-toe grid
// Search: Check if any student has a perfect score (100) public boolean hasPerfectScore() for (int row = 0; row < scores.length; row++) for (int col = 0; col < scores[row].length; col++) if (scores[row][col] == 100) return true;
In conclusion, manipulating 2D arrays in CodeHS is a powerful tool for working with grids, images, and other types of data that require multiple dimensions. By mastering the operations discussed in this piece, you will be able to create complex and interactive programs.
Manipulating 2D arrays is used in: