http://www.perlmonks.org?node_id=836178


in reply to Perl Program w/ Hash

Hash maintains the data as key-value pairs.
The data which is left to the operator '=>' is known as key.
And the data which is right to the operator '=>' is known as value.

Using keys you can get the value of a particular key in a hash in the following way.
$hash{'key'}

And keys should be unique.

In your case 'username' is a key and 'phone number' is a value.
So using username you can get the phone number of the user.
So,$friend{'username'} will give the phone number.