Newbie ruby array question

Ruby
1

Hi everyone,
I have this code from tryruby.
ratings = Hash.new(0)
books.values.each { |rate| ratings[rate] += 1 }

I was wondering if anyone can explain in plain english how ratings[rate]
is keeping count to be able to increase 1. In other languages to
increase 1 you need a variable to hold the count but how is it being
tallied up here? Can anyone help me I’m completely new with ruby. I
would be very grateful with any insight any of you gurus could pass on
to me.

Thank you,
sean.

2

Hash.new(0) creates a dictionary-type object with the default value of
0. Whatever “word” you search for, you get 0 back.

When you do “ratings[rate]” the first time for each book, you get a 0.
The zero then has 1 added to it and is put back into the Hash.

The second time that same book comes up, it returns a 1.
You then add another 1, making the Hash hold 2 for that book.

Rather than having a different variable for every book, you can now have
one variable that understands book names and can hold separate values
for each book.

3

Oh wow! Thanks Joel, You totally rock! Your explanation is right on
point! Just what I needed, couldn’t make sense of it before but now I
totally get it. Thanks so much.
Thank you,
sean.