Arrays: Codehs 8.1.5 Manipulating 2d

// Manipulation task 8.1.5 specific: Create diagonal pattern public static void diagonalOne(int[][] arr) for (int r = 0; r < arr.length; r++) for (int c = 0; c < arr[0].length; c++) if (r == c) arr[r][c] = 1; else if (r + c == arr.length - 1) arr[r][c] = 1; // Anti-diagonal also to 1 else arr[r][c] = 0;

Suppose you want to fill a blank 2D array with a specific starting value, such as setting every coordinate to -1 .

The goal of this assignment is to take a pre-existing 2D array and manipulate its contents based on specific criteria. Here is how to approach the common tasks involved. Step 1: Accessing Specific Elements

A 2D array is essentially an "array of arrays"—a grid consisting of rows and columns. Think of it like a spreadsheet, a chessboard, or a pixel grid. 1. Declaration and Initialization Codehs 8.1.5 Manipulating 2d Arrays

Instead of array[0].length in the inner loop, it is safer to use array[r].length . This handles "ragged arrays" (where rows have different lengths) correctly.

function doubleArray(matrix) for (let i = 0; i < matrix.length; i++) for (let j = 0; j < matrix[i].length; j++) matrix[i][j] *= 2;

// Search for a perfect score of 100 int targetScore = 100; boolean found = false; // Manipulation task 8

Depending on the exercise, you may need to return the modified grid or use println() to display the new state of the grid. Common Pitfalls and Troubleshooting

Run the autograder to see if your output matches the expected result.

for (let r = 0; r < grid.length; r++) for (let c = 0; c < grid[r].length; c++) console.log(grid[r][c]); Step 1: Accessing Specific Elements A 2D array

For each row, this starts at column 0 and goes up to the last column ( grid[0].length - 1 ).

Think of a 2D array as a table, a matrix, or, as the course describes it, "a grid, table, or list of lists". In Java, a 2D array is actually an "array of arrays." The row index refers to a specific one-dimensional array, and the column index picks an element within that array.

To successfully complete CodeHS 8.1.5, you must master the coordinate system and matrix boundaries.

Mastering CodeHS 8.1.5: Manipulating 2D Arrays Working with 2D arrays is a cornerstone of computer science, representing data in grids, tables, or matrices. In the curriculum, specifically in Module 8.1.5 , students move beyond simply creating 2D arrays to mastering the techniques required to manipulate, analyze, and traverse them.

for(int row = 0; row < grid.length; row++) for(int col = 0; col < grid[col].length; col++) // Access element: grid[row][col] Use code with caution. CodeHS 8.1.5: Manipulating 2D Arrays - Step-by-Step

// Manipulation task 8.1.5 specific: Create diagonal pattern public static void diagonalOne(int[][] arr) for (int r = 0; r < arr.length; r++) for (int c = 0; c < arr[0].length; c++) if (r == c) arr[r][c] = 1; else if (r + c == arr.length - 1) arr[r][c] = 1; // Anti-diagonal also to 1 else arr[r][c] = 0;

Suppose you want to fill a blank 2D array with a specific starting value, such as setting every coordinate to -1 .

The goal of this assignment is to take a pre-existing 2D array and manipulate its contents based on specific criteria. Here is how to approach the common tasks involved. Step 1: Accessing Specific Elements

A 2D array is essentially an "array of arrays"—a grid consisting of rows and columns. Think of it like a spreadsheet, a chessboard, or a pixel grid. 1. Declaration and Initialization

Instead of array[0].length in the inner loop, it is safer to use array[r].length . This handles "ragged arrays" (where rows have different lengths) correctly.

function doubleArray(matrix) for (let i = 0; i < matrix.length; i++) for (let j = 0; j < matrix[i].length; j++) matrix[i][j] *= 2;

// Search for a perfect score of 100 int targetScore = 100; boolean found = false;

Depending on the exercise, you may need to return the modified grid or use println() to display the new state of the grid. Common Pitfalls and Troubleshooting

Run the autograder to see if your output matches the expected result.

for (let r = 0; r < grid.length; r++) for (let c = 0; c < grid[r].length; c++) console.log(grid[r][c]);

For each row, this starts at column 0 and goes up to the last column ( grid[0].length - 1 ).

Think of a 2D array as a table, a matrix, or, as the course describes it, "a grid, table, or list of lists". In Java, a 2D array is actually an "array of arrays." The row index refers to a specific one-dimensional array, and the column index picks an element within that array.

To successfully complete CodeHS 8.1.5, you must master the coordinate system and matrix boundaries.

Mastering CodeHS 8.1.5: Manipulating 2D Arrays Working with 2D arrays is a cornerstone of computer science, representing data in grids, tables, or matrices. In the curriculum, specifically in Module 8.1.5 , students move beyond simply creating 2D arrays to mastering the techniques required to manipulate, analyze, and traverse them.

for(int row = 0; row < grid.length; row++) for(int col = 0; col < grid[col].length; col++) // Access element: grid[row][col] Use code with caution. CodeHS 8.1.5: Manipulating 2D Arrays - Step-by-Step