Largest multiple of n lower than x

Question

Most pythonic way avoiding for loops to find the largest number multiple of n but lower than an upperbound x?

Practical example:

n = 48 
x = 2636 

48 * 54 = 2592 is the nearest.

I am doing a for loop till I don't go over x now

Answer 1

The simplest way is probably using //:

(x // n) * n

If the number has to be strictly less than x, use x - 1 instead:

((x - 1) // n) * n

The expression x // n is the floor division of x by n, discarding any remainder.