Checking if a variable is not nil and not zero in ruby

Question

I am using the following code to check if a variable is not nil and not zero

if(discount != nil && discount != 0) 
  ...
end

Is the

Answer 1

Alternative solution is to use Refinements, like so:

module Nothingness
  refine Numeric do
    alias_method :nothing?, :zero?
  end

  refine NilClass do
    alias_method :nothing?, :nil?
  end
end

using Nothingness

if discount.nothing?
  # do something
end

Answer 2

From Ruby 2.3.0 onward, you can combine the safe navigation operator (&.) with Numeric#nonzero?. &. returns nil if the instance was nil and nonzero? - if the number was 0:

if discount&.nonzero?
  # ...
end

Or postfix:

do_something if discount&.nonzero?

Answer 3

I believe the following is good enough for ruby code. I don't think I could write a unit test that shows any difference between this and the original.

if discount != 0
end

Answer 4

unless discount.nil? || discount == 0
  # ...
end

Answer 5

def is_nil_and_zero(data)
     data.blank? || data == 0 
end  

If we pass "" it will return false whereas blank? returns true. Same is the case when data = false blank? returns true for nil, false, empty, or a whitespace string. So it's better to use blank? method to avoid empty string as well.

Answer 6

Yes, we do have a clean way in ruby.

discount.to_f.zero?

This check handles good amount of cases i.e. discount may be nil, discount may be int 0, discount may be float 0.0, discount may be string "0.0", "0".