mod(%)

X % Y

X and Y is a scalar/pair/vector/matrix. If X or Y is a pair/vector/matrix, the other is a scalar or a pair/vector/matrix of the same size.

mod means modulus. It returns the element-by-element remainder of X divided by Y. When Y is a positive integer, the modulus is always non-negative, e.g., -10 % 3 is 2. When Y is a negative integer, the modulus is always non-positive, e.g., -10 % -3 is -1.

Function mod is often used to group data. For example, [5,4,3,3,5,6]%3 is [2,1,0,0,2,0]; data can thereby be divided into three groups.

x=1 2 3;
x % 2;
// output
[1,0,1]

2 % x;
// output
[0,0,2]

y=4 5 6;
x mod y;
// output
[1,2,3]
mod(y, x);
// output
[0,1,0]

m=1..6$2:3;
m;

m mod 3;

x=-1 2 3;
x%-5;
// output
[-1,-3,-2]

-1%5;
// output
4