Manipulating 2D arrays in Java involves using nested for loops to traverse, access, and modify data stored in a grid-like structure. In CodeHS 8.1.5, the focus is on understanding how to iterate through these structures using row-major order to perform specific logic on individual elements.
Rows in 2D arrays can have different lengths (ragged arrays). To find the last index of any row safely, always use array[row].length - 1 rather than a fixed number. Codehs 8.1.5 Manipulating 2d Arrays
The core mechanism for manipulating a 2D array is the nested for loop. Because a 2D array is essentially an "array of arrays," a single loop is insufficient to reach every element. The outer loop typically iterates through the rows, while the inner loop traverses the columns of the current row. This structure provides a coordinate-like system, where every element is accessible via its row and column indices. In 8.1.5, learners practice how to use these indices not just to read data, but to modify it—whether by initializing a grid with specific values, updating a single entry, or transforming the entire data set based on a logical condition. Manipulating 2D arrays in Java involves using nested