In Ruby, if the value of
a key inside a hash is not
specified, it will be assigned
a default value of nil.
From Ruby version 3.1,
we have an option to omit
the value in a hash,
provided that we have a
variable in scope with the
same name as the key.
The value stored in the
variable will be assigned
to the key inside the hash.
Let us take a look at
a few examples:
As we can see from the above code,
both mammals and animals hash
have the same values.
When using the shorthand,
make sure never to add variables as
a string. Doing this will throw
an error.
Let us look at another example: