Ruby beginner Problem


#1

I get the following error message when running the code below:
undefine method ‘bottles _of_beer’ for #Bottles:0x2be1e1c
(NoMethodError)

To change this template, choose Tools | Templates

and open the template in the editor.

class Bottles
def initialize (bottles_of_beer, bottle_word, one_word)
@bottles_of_beer = bottles_of_beer
@bottle_word = bottle_word
@one_word = one_word

         end

my_bottles = Bottles.new(99,‘Bottles’,‘Bottle’)

   while my_bottles.bottles_of_beer >= 2
 puts "#{my_bottles.bottles_of_beer} #{my_bottles.bottle_word} of

beer on the wall"
puts “#{my_bottles.bottles_of_beer} #{my_bottles.bottle_word} of beer”
puts “Take one down, pass it around”

my_bottles.bottles_of_beer -= 1

if my_bottles.bottles_of_beer == 1
puts “#{my_bottles.bottles_of_beer} bottle of beer on the wall”

else
puts “#{my.bottles.bottles_of_beer} #{my_bottles.bottle_word}of beer
on the wall”

end

if my_bottles.bottles_of_beer == 1
puts “#{my_bottles.bottles_of_beer} #{my_bottles.one_word} of beer on
the wall”
puts “#{my_bottles.bottles_of_beer} #{my_bottles.one_word} of beer”
puts “Take one down, pass it around”

my_bottles.bottles_of_beer -= 1

puts “No more #{my_bottles.bottle_word} of beer on the wall”

end

end

end

Yeah I know this code is horribly formatted. I’m using Vim text editor, and have not yet figured out how to auto format my code.
What am I doing wrong? I still have a very long way to go, and practice alot more.

Thanks
Zayd


#2

Zayd C. wrote:

I get the following error message when running the code below:
undefine method ‘bottles _of_beer’ for #Bottles:0x2be1e1c
(NoMethodError)

class Bottles
def initialize (bottles_of_beer, bottle_word, one_word)
^

Ruby is space sensitive between the end of a method name and its first
parameter. You gotta take that space out.

In general, I don’t know what other languages and editors you have
learned, but
Ruby is very easy to format correctly via muscle memory. Just set your
tabs to 2
spaces (no \t tab characters), and turn on the autoindent. From there,
keeping
everything correctly formatted is quite simple, and this will lead, in
turn, to
fewer syntax errors.

I remember a Visual Basic Classic that would have removed that space,
for
example, but I know no Ruby editor which will does that for you!


#3

Whoa, thats all to it, I need to get my formatting down right now =)
This is my first language so I have a long way to travel:) now this is
something I will be aware of in the future.

Thank you


#4

On Sun, Mar 1, 2009 at 10:46 AM, Zayd C. removed_email_address@domain.invalid
wrote:

I’m using Vim text editor, and have not yet figured out how to auto format my code.

:h =

In Normal mode, hitting == will format the current line.
It takes the usual motion prefixes, so e.g. 5== will format the next 5
lines.
In Visual mode, = will format the selection.

This should work for any recognized file type. Most standard vim
installs include the ruby filetype plugin. If yours doesn’t or needs
upgrading, see:
http://tinyurl.com/dd2ef9

Solidarity,
lasitha.


#5

Zayd A. wrote:

def initialize(bottles_of_beer, bottle_word, one_word)
    @bottles_of_beer = bottles_of_beer
    @bottle_word = bottle_word
    @one_word = one_word

end

All the code past this point is in a very odd place. You seem to be
missing the rest of your Bottles class definition. Try adding another
‘end’ here.

 my_bottles = Bottles.new(99,'Bottles','Bottle')


while my_bottles.bottles_of_beer >= 2

The error is right here because you never defined a bottles_of_beer
method for Bottles. In fact, you are still inside the Bottles class
definition, which I think you just forgot to close after the initialize
method.
You cannot access instance variables (@…) from outside of an object.
You have to define attribute setters and readers to provide the access.
Try using:

attr_accessor :bottles_of_beer
attr_reader :bottle_word, :one_word

These typically go right before your initialize method.You can read
about them here:
http://ruby-doc.org/docs/ProgrammingRuby/html/tut_classes.html

    else
        puts "#{my.bottles.bottles_of_beer} #{my_bottles.bottle_word}of

beer on the wall"

Typo above, should be my_bottles not my.bottles

        my_bottles.bottles_of_beer -= 1

        puts "No more #{my_bottles.bottle_word} of beer on the wall"

    end

None of this code should be in your class…end section.

-Justin


#6

Thanks Lasitha that worked perfect. I’m slowly getting more comfortable
with
just the basic :slight_smile:
I’m still getting that same error when compiling my code. I know its
right
there in front of my face I just can’t put my finger on it

Kindest Regards
Zayd

class Bottles
def initialize(bottles_of_beer, bottle_word, one_word)
@bottles_of_beer = bottles_of_beer
@bottle_word = bottle_word
@one_word = one_word

end


 my_bottles = Bottles.new(99,'Bottles','Bottle')


while my_bottles.bottles_of_beer >= 2       <<*The error is pointing 

to
this line*
puts “#{my_bottles.bottles_of_beer} #{my_bottles.bottle_word} of
beer on the wall”
puts “#{my_bottles.bottles_of_beer} #{my_bottles.bottle_word} of
beer”
puts “Take one down, pass it around”

    my_bottles.bottles_of_beer -= 1

    if my_bottles.bottles_of_beer == 1
        puts "#{my_bottles.bottles_of_beer} bottle of beer on the 

wall"

    else
        puts "#{my.bottles.bottles_of_beer} 

#{my_bottles.bottle_word}of
beer on the wall"

    end


    if my_bottles.bottles_of_beer == 1
        puts "#{my_bottles.bottles_of_beer} #{my_bottles.one_word} 

of
beer on the wall"
puts “#{my_bottles.bottles_of_beer} #{my_bottles.one_word}
of
beer”
puts “Take one down, pass it around”

        my_bottles.bottles_of_beer -= 1

        puts "No more #{my_bottles.bottle_word} of beer on the wall"

    end


end

end


#7

Zayd A. wrote:

So the reason bottles_of_beer is attr_accessor is because I have to access
it to change the value of it, and bottle_word and one_word are attr_readers,
because those values never change?

Short term, use accessors to get to your instance variables.

Long term, learn the principle “tell don’t ask.” Don’t ask your object
for its
variables, then use them. Instead, tell the object what to do, and let
it use
its variables to do it.

In your sample program, each phase (checking the beer bottle count,
singing
about one bottles, decrementing the count) could have ran inside a
method in
Bottles.


#8

Phlip wrote:

Ruby is space sensitive between the end of a method name and its first
parameter.

Erm, what? No it’s not. I just tried something like this in irb, and it
worked fine.


#9

On Sun, Mar 1, 2009 at 1:24 AM, lasitha removed_email_address@domain.invalid
wrote:

On Sun, Mar 1, 2009 at 10:46 AM, Zayd C. removed_email_address@domain.invalid wrote:

I’m using Vim text editor, and have not yet figured out how to auto format my code.

:h =

In Normal mode, hitting == will format the current line.
It takes the usual motion prefixes, so e.g. 5== will format the next 5 lines.
In Visual mode, = will format the selection.

Thanks for posting this, even though I’ve been using vim forever, I
never bothered to look up how to do auto-formatting.

-greg


#10

On Sun, Mar 1, 2009 at 1:39 PM, Phlip removed_email_address@domain.invalid wrote:

Long term, learn the principle “tell don’t ask.” Don’t ask your object for
its variables, then use them. Instead, tell the object what to do, and let
it use its variables to do it.

In your sample program, each phase (checking the beer bottle count, singing
about one bottles, decrementing the count) could have ran inside a method in
Bottles.


Phlip

Like this. I just created two methods in the Bottles class that sings the
bottles song. I’m sure theres some cleaning up to do, Am I still doing
to
much outside of the class, can I add more to these methods?

class Bottles

attr_accessor :bottles_of_beer

attr_reader  :bottle_word, :one_word

def initialize(bottles_of_beer, bottle_word, one_word)
    @bottles_of_beer = bottles_of_beer
    @bottle_word = bottle_word
    @one_word = one_word

end

def beersong
    puts "#{bottles_of_beer} #{bottle_word} of beer on the wall"
    puts "#{bottles_of_beer} #{bottle_word} of beer"
    puts "Take one down, pass it around"

end

def beersong_two
    puts "#{bottles_of_beer} #{one_word} of beer on the wall"
    puts "#{bottles_of_beer} #{one_word} of beer"
    puts "Take one down, pass it around"
end

end

my_bottles = Bottles.new(99, ‘Bottles’, ‘Bottle’)

while my_bottles.bottles_of_beer >= 2

my_bottles.beersong
my_bottles.bottles_of_beer -=1

if my_bottles.bottles_of_beer > 1
    puts "#{my_bottles.bottles_of_beer} bottles of beer on the wall"
else
    puts "#{my_bottles.bottles_of_beer} bottle of beer on the wall"
end

if my_bottles.bottles_of_beer == 1

    my_bottles.beersong_two
    puts "No more #{my_bottles.bottle_word} of beer on the wall"

    end

end


#11

Thanks Justin.
So the reason bottles_of_beer is attr_accessor is because I have to
access
it to change the value of it, and bottle_word and one_word are
attr_readers,
because those values never change?

Here goes my new code that worked just fine

class Bottles

attr_accessor :bottles_of_beer

attr_reader  :bottle_word, :one_word

def initialize(bottles_of_beer, bottle_word, one_word)
    @bottles_of_beer = bottles_of_beer
    @bottle_word = bottle_word
    @one_word = one_word

end

end

my_bottles = Bottles.new(99, ‘Bottles’, ‘Bottle’)

while my_bottles.bottles_of_beer >= 2
puts “#{my_bottles.bottles_of_beer} #{my_bottles.bottle_word} of
beer on
the wall”
puts “#{my_bottles.bottles_of_beer} #{my_bottles.bottle_word} of
beer”
puts “Take one down, pass it around”

my_bottles.bottles_of_beer -= 1

if my_bottles.bottles_of_beer == 1
    puts "#{my_bottles.bottles_of_beer} bottle of beer on the wall"

else
    puts "#{my_bottles.bottles_of_beer} #{my_bottles.bottle_word} of

beer on the wall"

end


if my_bottles.bottles_of_beer == 1
    puts "#{my_bottles.bottles_of_beer} #{my_bottles.one_word} of 

beer
on the wall"
puts “#{my_bottles.bottles_of_beer} #{my_bottles.one_word} of
beer”
puts “Take one down, pass it around”

    my_bottles.bottles_of_beer -= 1

    puts "No more #{my_bottles.bottle_word} of beer on the wall"




end

end


#12

I don’t think you actually need a class at all You’re just calling a
procedure.


#13

<<< I don’t think you actually need a class at all You’re just calling a
procedure.

Thanks, but I was just trying to practice using classes, and instance
variables :slight_smile:
However I did find a quicker approach using less code to run this
program
without using class. See Below

bottles = 99

98.times do |num|
puts “#{bottles} bottles of beer on the wall”
puts “#{bottles} bottles of beer”
puts “Take one down pass it around”
bottles -=1
puts “#{bottles} bottles of beer on the wall” unless bottles == 1

if bottles == 1
    puts "#{bottles} bottle of beer on the wall"
    puts "#{bottles} bottle of beer on the wall"
    puts "#{bottles} bottle of beer"
    puts "Take one down pass it around"
    puts "No more bottles of beer on the wall"
end

end

Kindest Regards
Zayd


#14

On Sun, Mar 1, 2009 at 12:23 PM, Zayd A. removed_email_address@domain.invalid
wrote:

if my_bottles.bottles_of_beer == 1

end

end

Just to explore the language a bit…

module Grammar
Noun = Struct.new( :singular, :plural, :collective )
end
include Grammar
bottleness = Noun.new( “bottle”, “bottles”, “case” )
10.downto(1) do |i|
puts("#{i} #{i == 1 ? bottleness.singular : bottleness.plural} of
beer on the wall")
end

…of course you’d need to add the other phrases of the sing/song in
there. Why a module? I guess it just seemed to make sense at the
moment. Why a Struct? Because it builds accessors for me
automatically.

In reality, I’d try to separate the execution code from the string
phrases (I pretty much try to avoid the #{} as much as I can).

One thing interesting I should mention, though, is that the #{}
construct can be used to not only display variable values, but also
method results, and even expressions, so…

99.downto(1) do |i|
suffix = (i == 1 ? ‘’ : ‘s’)
puts “#{i} bottle#{suffix} of beer on the wall,”
puts “#{i} bottle#{suffix} of beer,”
puts “Take one down pass it around,”
puts “#{i-1} bottle#{‘s’ unless i == 2} of beer on the wall.\n”
#that last line actually works
puts
end

…simple method example…

def foo
‘hi’
end

puts “{#foo} there”

…but, like I said. Finding a way to separate static data from
logical data is usually the best route for good code (which I have
not done in the above examples). And don’t forget for that last
edge case, namely, “No more” for zero.

hth,
Todd


#15

On Mon, Mar 2, 2009 at 2:49 PM, Todd B. removed_email_address@domain.invalid wrote:

…simple method example…

def foo
‘hi’
end

puts “{#foo} there”

This obviously was supposed to read…

puts “#{foo} there”


#16

Cool!, Wow, there are so many ways to do one thing. I’m going to try and
test this out. I guess that is a good way to enhance ones skill, build
simple programs, and try it in different ways.

Kindest Regards


#17

On Mon, Mar 2, 2009 at 2:25 PM, Zayd A. removed_email_address@domain.invalid
wrote:

Cool!, Wow, there are so many ways to do one thing.

Yeah, I know. You should check out ruby quiz answers; so many good
ways of doing the same quiz that changes weekly (if you haven’t seen
it). I am truly lowly compared to most of these people :slight_smile:

I tried my hand at the quiz several times, but was embarrassed with my
code, lol! Good for learning though. Most of the quiz contributors
are very good at commenting what they are doing.

Todd


#18

I think I’m going to try a few quiz’s out, I never tried before, I just
wanted to wait until I was comfortable with the basic foundations of
Ruby.
Thanks for your help, and suggestions =). Maybe I’lllook for the easy
ones
first, then take a look at the difficult ones.

Kindest Regards
Zayd