In Lua, how can I tell if a number divides evenly into another number?

Question

In Lua, how can I tell if a number divides evenly into another number? i.e with no remainder? I'm just looking for a boolean true or false.

12/6 = 2 (true)
18/6 = 3 (true)
20/6 = 3.(3) (false)

Solution

Compare the remainder of the division to zero, like this:

12 % 6 == 0

18 % 6 == 0

20 % 6 ~= 0

The modulus operator (%) returns the remainder of division. For 12 and 6 it is 0, but for 20 and 6 it is 2.

The formula it uses is: a % b == a - math.floor(a/b)*b

Comments

[etandel]

The cool thing about % is that it works on real numbers as well

[BMitch]

For comparisons to 0, the modulus operator appears to work fine. No need to make an extra function call.

[Eric]

Whether -13 % 6 == 5 is incorrect a matter of opinion. This is often the behaviour you want.