Nothingness and the Truth
Learn about truthiness, falsiness, and nothingness.
Now is a good time to explore the concepts of nothingness and truth in Ruby. First, let’s also do a quick recap to build some context.
The nil object
We’ve briefly mentioned that in Ruby, there’s an object that represents nothing, nil.
Remember how we can receive a value associated with a key from a hash?
dictionary = { :one => "eins", :two => "zwei", :three => "drei" }p dictionary[:one]
This prints out "eins". However, what happens if we try to receive the value for a key that hasn’t been defined on the hash?
dictionary = { :one => "eins", :two => "zwei", :three => "drei" }p dictionary[:four]
This prints out nil. Remember that every method call always returns some value. In cases where there’s nothing to return, it returns nil, which represents nothing.
Note that nil isn’t 0, which represents something. An empty string (""), an empty array ([]), or an empty hash ({}) also all represent something. So, they’re not nil. ...