Checking if a variable is not nil and not zero in ruby
unless discount.nil? || discount == 0 # ... end
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.
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.
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?