Best ruby idiom for “nil or zero”

Question

I am looking for a concise way to check a value to see if it is nil or zero. Currently I am doing something like:

if (!val || val == 0)
  # Is nil or zero
e         


        

Answer 1

To be as idiomatic as possible, I'd suggest this.

if val.nil? or val == 0
    # Do something
end

Because:

• It uses the nil? method.
• It uses the "or" operator, which is preferable to ||.
• It doesn't use parentheses, which are not necessary in this case. Parentheses should only be used when they serve some purpose, such as overriding the precedence of certain operators.

Answer 2

Short and clear

[0, nil].include?(val)

Answer 3

Shortest and best way should be

if val&.>(0)
  # do something
end

For val&.>(0) it returns nil when val is nil since > basically is also a method, nil equal to false in ruby. It return false when val == 0.

Answer 4

val ||= 0
if val == 0
# do something here
end

Answer 5

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:

unless val&.nonzero?
  # Is nil or zero
end

Or postfix:

do_something unless val&.nonzero?

Answer 6

I deal with this by defining an "is?" method, which I can then implement differently on various classes. So for Array, "is?" means "size>0"; for Fixnum it means "self != 0"; for String it means "self != ''". NilClass, of course, defines "is?" as just returning nil.