If you swap elements in the same loop where you iterate, you may double-swap. For column swaps, simply loop through rows; don't loop twice.
function getEvens(matrix) let result = []; for (let i = 0; i < matrix.length; i++) let evenRow = []; for (let j = 0; j < matrix[i].length; j++) if (matrix[i][j] % 2 === 0) evenRow.push(matrix[i][j]); Codehs 8.1.5 Manipulating 2d Arrays
: Change the final value to the length of the first row . If you swap elements in the same loop
At its core, the exercise challenges students to understand that a 2D array is essentially an "array of arrays." This conceptual leap requires a shift in thinking from a single linear index to a coordinate system involving rows and columns. The primary learning objective of 8.1.5 is to master the nested loop structure. To manipulate every element in a grid, one loop is required to iterate through the rows, while a second, nested loop iterates through the columns. This structure is the foundational rhythm of 2D array processing: for (int i = 0; i < array.length; i++) controlling the outer traversal, and for (int j = 0; j < array[i].length; j++) controlling the inner traversal. At its core, the exercise challenges students to
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