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

Solution 1:

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

Solution 2:

class Object
  def nil_zero?
    self.nil? || self == 0
  end
end

# which lets you do
nil.nil_zero? # returns true
0.nil_zero?   # returns true
1.nil_zero?   # returns false
"a".nil_zero? # returns false

unless discount.nil_zero?
  # do stuff...
end

Beware of the usual disclaimers... great power/responsibility, monkey patching leading to the dark side etc.

Solution 3:

ok, after 5 years have passed....

if discount.try :nonzero?
  ...
end

It's important to note that try is defined in the ActiveSupport gem, so it is not available in plain ruby.