Re: Another noob question

On Mon, Mar 29, 2010 at 4:55 PM, Omar Velez <[e-mail]> wro=
te:
> Thanks to everyone that helped me a few days ago. =A0This time I am tryin=
g
> to write a program that incorporates everything that I have learned in
> the last week but I am more than sure that I am making mistakes
> somewhere. =A0Also there is somethings I do not know how to do.
> Everything is commented so it should be easy to find. =A0Also if anyone
> has any suggestions about my syntax style please give me advice. =A0Thank=
s
> again everyone!
>
> _______________________________________
>
> # Program written by Dr. Omar Israel Velez
>
> # This program will try to integrate several concepts that I have
> learned so far
> # =A0The program will ask for some basic information and then it will ask
> for a
> # list of favorite books. =A0Afterwards it will sum up the total number o=
f
> # characters in the book titles and add how many of each letter there
> are.
> # finally it will offer a new book as a suggestion based on which letter
> was the
> # most popular.
>
> puts "What\s your first name?" ; first_name =3D gets.chomp ; puts
> puts "What\'s your last name?" ; last_name =3D gets.chomp ; puts
>
> puts "Well, #{first_name} #{last_name}, tell me four books that you have
> read:"
> puts

# > books_one =3D gets.chomp ; books_two =3D gets.chomp
# > books_three =3D gets.chomp ; books_four =3D gets.chomp
# > all_books =3D ["#{books_one.downcase}", "#{books_two.downcase}",
# > "#{books_three.downcase}", "#{books_four.downcase}"].sort

all_books =3D []
4.times do
   all_books << gets.chomp.downcase
end

all_books.sort!

>
> # Is there a more efficient way to write this code where I don't have to
> # isolate each one and I can downcase everything at once?
>
> puts
>
> puts "These are the books that you entered #{first_name}." ; puts

# > all_books.each do |books|
# > =A0puts books
# > end

puts books

>
> puts
>
> puts "#{first_name} are these books correct?" ; answer =3D gets.chomp ;
> puts
>
> if answer =3D=3D 'yes'
> =A0puts "Ah, very good choice of books #{first_name}."
> else
> =A0puts "Well computers never make mistakes so it must be in your head."
> =A0puts "Run the program again please."

     exit

> end
>
> puts
>
# > a =3D books_one.length ; b =3D books_two.length
# > c =3D books_three.length ; d =3D books_four.length
> # =A0Same question as before, can I .length everything at the same time
> and make
> # =A0the code more efficient?
>
# > total_characters =3D a + b + c + d

total_characters =3D all_books.inject(0) {|total, book| total + book.length=
}

>
> # =A0I cheated and just went with the total number of characters. =A0But =
how
> do I
> # =A0add up the total number of each letter and then suggest a book for
> each letter?
> # =A0just two or three examples will be ok I know asking for 26 examples
> is just crazy.

# The letter histogram
h =3D Hash.new(0)
all_books.each {|b| b.split(//).each {|letter| h[letter] +=3D 1}}

If you want to suggest a book for each letter, you'll have to have a
list of books by letter. Something like:

recommendations =3D {'a' =3D> "A whatever", 'b' =3D> "because..."} # Crazy =
!
I didn't come up with any book title !!!! (I'm not a native speaker)

Then you can recommend based on the present letters, if I understood correc=
tly:

h.keys.each {|initial| puts "I recommend: #{recommendations[initial]}"}

> puts "There are #{total_characters} total characters in the tittles you
> read."
> puts
>
> if total_characters >=3D 50
> =A0puts "I recommend reading The Hobbit."
> =A0puts "There is a #{rand(101)}% chance you will like this book."
> =A0puts "Would you like to read this book?" ; answer =3D gets.chomp ; put=
s
> =A0if answer =3D=3D 'yes'
> =A0 =A0puts "I am sure that you will enjoy it #{first_name}"
> =A0else
> =A0 =A0puts "Oh that is too bad, how about Animal Farm then?"
> =A0 =A0puts "There is a #{rand(101)}% chance you will like this book."
> =A0end
> else
> =A0puts "I recommend you read The Tale of Two Cities."
> =A0puts "There is a #{rand(101)}% chance you will like this book."
> =A0puts "Would you like to read this book #{first_name}?" ; answer =3D
> gets.chomp
> =A0puts
> =A0if answer =3D=3D 'yes'
> =A0 =A0puts "I am sure that you will have a great time reading it!"
> =A0else
> =A0 =A0puts "Ok then, how about A Day in the Life of Alex Jones?"
> =A0 =A0 puts "There is a #{rand(101)}% chance you will like this book."
> =A0end
> end

Whenever you see duplicated code, that's a good place to refactor:

def recommend(name, books)
  books.each do |book|
     puts "I recommend you read #{book}"
     puts "There's a #{rand(101)}% chance you'll like it"
     puts "Would you like to read this book #{name}?"
     answer =3D gets.chomp
     if answer =3D=3D "yes"
       puts "I'm sure you'll like it"
       break
     end
  end
end

or something like that, then:

if total_characters < 50
   recommend(first_name, ["The Hobbit", "Animal Farm"])
else
   recommend(first_name, ["The Tale of Two Cities", "A Day in the Life
of Alex Jones"])
end

Well, this is not exactly equivalent to your code, but you get the idea.

>
> # =A0I also tried to create a global constant like so..
> # =A0percent =3D =A0"There is a #{rand(101)}% chance you will like this b=
ook."
> # =A0and then point to it to make the code look cleaner but it would not
> let me.
> # =A0How would I do this?

What didn't work?

percent =3D "There is a #{rand(101)} chance you'll like it"
puts percent

works for me. If you mean that it's always the same percentage, then
make it a method:

def percentage_sentence
  "There is a #{rand(101)} chance you'll like it"
end

puts percent

Jesus.