在JS中以最干净，最紧凑的方式对角矩阵在所有可能的方向上进行迭代

function iterateDiagonally(matrix,main,rightToLeft,topToBottom)
{
for(let a = 0,b = matrix.length + matrix[0].length - 1; a {
let x = main ? Math.min(a,matrix.length - 1) : Math.max(0,a - matrix[0].length + 1);
let y = main ? Math.min(matrix[0].length - 1,matrix.length + 1 - a) : Math.min(a,matrix[0].length - 1);
for(let c = 0,d = Math.min(y + 1,main ? x + 1 : matrix.length - x); c {
let eX = main ? x - c : x + c;
let eY = y - c;
console.log(matrix[eX][eY]);
}
}
}
/*
1 4 7
2 5 8
3 6 9
*/
console.log("Along the main diagonal");
iterateDiagonally([[1,2,3],[4,5,6],[7,8,9]],true);
console.log("Along the antidiagonal");
iterateDiagonally([[1,false);

function iterateDiagonally(matrix,main,rightToLeft,topToBottom)
{
// Move along half of the perimeter,excluding the duplicate corner element
// a - first element of each diagonal
// b - amount of diagonals in total
for(let a = 0,b = matrix.length + matrix[0].length - 1; a {
// For the main diagonal,first move right along the x axis starting with the bottom left element,then move up the y axis
// For the antidiagonal,first move down the y axis starting with the top left element,then move right along the x axis
let x = main ? Math.min(a,matrix.length - 1) : Math.max(0,a - matrix[0].length + 1);
let y = main ? Math.min(matrix[0].length - 1,matrix.length + 1 - a) : Math.min(a,matrix[0].length - 1);
// Invert the starting position and direction of all movement
if(rightToLeft) x = matrix.length - 1 - x,y = matrix[0].length - 1 - y;
let diagOnal= [];
// Move along each diagonal
// c - element of diagonal
// d - amount of elements in diagonal in total
for(let c = 0,d = Math.min(rightToLeft ? matrix[0].length - y : y + 1,main !== rightToLeft ? x + 1 : matrix.length - x); c {
// Invert the diagonal traversal order
let iC = topToBottom !== rightToLeft ? d - 1 - c : c;
// X coordinate of the element
let eX = main !== rightToLeft ? x - iC : x + iC;
// Y coordinate of the element
let eY = rightToLeft ? y + iC : y - iC;
diagonal.push(matrix[eX][eY]);
}
console.log(diagonal.join(","));
}
}
/*
1 4 7
2 5 8
3 6 9
*/
console.log("Parallel main diagonal,left to right,bottom to top");
iterateDiagonally([[1,9]],true,false,false);
console.log("Parallel main diagonal,right to left,top to bottom");
iterateDiagonally([[1,true);
console.log("Parallel main diagonal,true);
console.log("Parallel antidiagonal,false);
console.log("Parallel antidiagonal,true);