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nil? will only return true if the object itself is nil. That means that an empty string is NOT nil and an empty array is NOT nil.
In Ruby, nil is a special value that denotes the absence of any value. Nil is an object of NilClass. nil is Ruby's way of referring to nothing or void. Ruby also provide a nil?
Use the [] Syntax to Check Whether a String Contains a Substring in Ruby. For accessing a character in a string at a specific index, we could use the [] syntax. The interesting thing about this syntax is that if we pass in a string, it will return a new string that is matched; otherwise, it will return nil .
When I'm not worried about performance, I'll often use this:
if my_string.to_s == ''
# It's nil or empty
end
There are various variations, of course...
if my_string.to_s.strip.length == 0
# It's nil, empty, or just whitespace
end
If you are willing to require ActiveSupport you can just use the #blank? method, which is defined for both NilClass and String.
I like to do this as follows (in a non Rails/ActiveSupport environment):
variable.to_s.empty?
this works because:
nil.to_s == ""
"".to_s == ""
An alternative to jcoby's proposal would be:
class NilClass
def nil_or_empty?
true
end
end
class String
def nil_or_empty?
empty?
end
end
As it was said here before Rails (ActiveSupport) have a handy blank? method and it is implemented like this:
class Object
def blank?
respond_to?(:empty?) ? empty? : !self
end
end
Pretty easy to add to any ruby-based project.
The beauty of this solution is that it works auto-magicaly not only for Strings but also for Arrays and other types.
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