Ruby: divisible by 4

问题

This works fine, but I want to make it prettier - and accommodate all values that are divisible by 4:

if i==4 || i==8 || i==12 || i==16 || i==20 || i==24 || i==28 || i==32
  # ...
end

Any clever, short method to do this?

回答1:

Try this:

if i % 4 == 0

This is called the "modulo operator".

回答2:

There's also modulo, which allows you to do

420.modulo(4).zero?

There's nothing stopping you doing that with %, but it looks weird:

420.%(4).zero?

回答3:

This is always a good conversation starter:

if (i & 3).zero?

来源：https://stackoverflow.com/questions/8817927/ruby-divisible-by-4