Sometimes the manipulation depends on where the element is located. if (row % 2 == 0) Identify the Diagonal: if (row == col) Identify the Last Column: if (col == array[row].length - 1) 3. Mathematical Transformations
Performing mathematical operations on every element, like doubling every value in the array.
For example:
The most common way to visit every element is a loop:
CodeHS 8.1.5 “Manipulating 2D Arrays” is your gateway to understanding one of the most important data structures in AP Computer Science. By mastering the nested‑loop traversal and learning to create new arrays based on old ones, you’ve built a skill that will appear repeatedly: in image processing, board games (like tic‑tac‑toe or chess), spreadsheet calculations, and many real‑world applications.
In this specific exercise, you are typically asked to modify an existing 2D array. This often involves: through every element using nested loops. Evaluating the current value at a specific position.
In CodeHS 8.1.5, you are often asked to initialize these with specific values or use nested loops to fill them. 2. Traversing 2D Arrays (Nested Loops)
Always remember the syntax is matrix[row][col] . Putting the column loop on the outside or swapping indices ( matrix[col][row] ) will cause errors or crashes if the grid is not perfectly square.
Call your method three times with the specific logic required for each row. updateValue(array, 0, array[0].length - 1, array.length); updateValue(array, 1, array[1].length - 1, totalElements);
var array = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]; var element = array[1][1]; // access element at row 1, column 1 console.log(element); // output: 5