IO output problem

ruby-talk
1

I run one of examples of Programming Ruby, code as follows:

···

------------
class Sone
...
end

song = Sone.new(.., .., ..)
song.inspect
song.to_s
-----------
why I can't see output? where is output of inspect and to_s ?
It outputs to somewhere else? IO object ?

thank you in advance

2

Hi --

I run one of examples of Programming Ruby, code as follows:
------------
class Sone
...
end

song = Sone.new(.., .., ..)
song.inspect
song.to_s
-----------
why I can't see output? where is output of inspect and to_s ?
It outputs to somewhere else? IO object ?

inspect and to_s just produce strings. To see them, you have to print
them :slight_smile: In fact, there are some handy methods for this:

   p song # automatically calls inspect
   puts song # automatically calls to_s

Also, if you are working in irb (the interactive Ruby terminal),
you'll see the value of every expression you type in. So in irb, if
your expression evaluates to a string, you'll see the string without
having to explicitly ask for it to be printed.

David

···

On Fri, 15 Dec 2006, Kevin wrote:

--
Q. What's a good holiday present for the serious Rails developer?
A. RUBY FOR RAILS by David A. Black (http://www.manning.com/black\)
    aka The Ruby book for Rails developers!
Q. Where can I get Ruby/Rails on-site training, consulting, coaching?
A. Ruby Power and Light, LLC (http://www.rubypal.com)

3

First, Song is misspelled to Sone, it seems.

To answer your question, use puts song.to_s to display output. Puts is technically a method of Kernel, but you can use it as just puts anywhere in your Ruby program.

Gets does (kind of) the opposite of puts and "gets" what a user at the command line typed.

Dan

Kevin wrote:

···

I run one of examples of Programming Ruby, code as follows:
------------
class Sone
...
end

song = Sone.new(.., .., ..)
song.inspect
song.to_s
-----------
why I can't see output? where is output of inspect and to_s ?
It outputs to somewhere else? IO object ?

thank you in advance

4

I understand now, thank you both of you
dblack@wobblini.net wrote:

···

Hi --

On Fri, 15 Dec 2006, Kevin wrote:

> I run one of examples of Programming Ruby, code as follows:
> ------------
> class Sone
> ...
> end
>
> song = Sone.new(.., .., ..)
> song.inspect
> song.to_s
> -----------
> why I can't see output? where is output of inspect and to_s ?
> It outputs to somewhere else? IO object ?

inspect and to_s just produce strings. To see them, you have to print
them :slight_smile: In fact, there are some handy methods for this:

   p song # automatically calls inspect
   puts song # automatically calls to_s

Also, if you are working in irb (the interactive Ruby terminal),
you'll see the value of every expression you type in. So in irb, if
your expression evaluates to a string, you'll see the string without
having to explicitly ask for it to be printed.

David

--
Q. What's a good holiday present for the serious Rails developer?
A. RUBY FOR RAILS by David A. Black (http://www.manning.com/black\)
    aka The Ruby book for Rails developers!
Q. Where can I get Ruby/Rails on-site training, consulting, coaching?
A. Ruby Power and Light, LLC (http://www.rubypal.com)

5

Hi --

To answer your question, use puts song.to_s to display output.

Or just puts song. to_s will be called automatically:

irb(main):001:0> o = Object.new
=> #<Object:0xb7f06840>
irb(main):002:0> def o.to_s; "Here I am!"; end
=> nil
irb(main):003:0> puts o
Here I am!

:slight_smile:

David

···

On Fri, 15 Dec 2006, Daniel Finnie wrote:

--
Q. What's a good holiday present for the serious Rails developer?
A. RUBY FOR RAILS by David A. Black (http://www.manning.com/black\)
    aka The Ruby book for Rails developers!
Q. Where can I get Ruby/Rails on-site training, consulting, coaching?
A. Ruby Power and Light, LLC (http://www.rubypal.com)

6

It's been a while since I've read that example but for some reason, I
remember thinking it was just an example to show how Ruby's object
orientation worked... not a real functional example. Perhaps it was
and I completely missed it. Dunno..

···

On 12/14/06, Kevin <coscpp@gmail.com> wrote:

I understand now, thank you both of you
dblack@wobblini.net wrote:
> Hi --
>
> On Fri, 15 Dec 2006, Kevin wrote:
>
> > I run one of examples of Programming Ruby, code as follows:
> > ------------
> > class Sone
> > ...
> > end
> >
> > song = Sone.new(.., .., ..)
> > song.inspect
> > song.to_s
> > -----------
> > why I can't see output? where is output of inspect and to_s ?
> > It outputs to somewhere else? IO object ?
>
> inspect and to_s just produce strings. To see them, you have to print
> them :slight_smile: In fact, there are some handy methods for this:
>
> p song # automatically calls inspect
> puts song # automatically calls to_s
>
> Also, if you are working in irb (the interactive Ruby terminal),
> you'll see the value of every expression you type in. So in irb, if
> your expression evaluates to a string, you'll see the string without
> having to explicitly ask for it to be printed.
>
> David
>
> --
> Q. What's a good holiday present for the serious Rails developer?
> A. RUBY FOR RAILS by David A. Black (http://www.manning.com/black\)
> aka The Ruby book for Rails developers!
> Q. Where can I get Ruby/Rails on-site training, consulting, coaching?
> A. Ruby Power and Light, LLC (http://www.rubypal.com)

7

I think it's from Programming Ruby: The Pragmatic Programmer's Guide. http://www.rubycentral.com/book/tut_threads.html

dan

x1 wrote:

···

It's been a while since I've read that example but for some reason, I
remember thinking it was just an example to show how Ruby's object
orientation worked... not a real functional example. Perhaps it was
and I completely missed it. Dunno..

On 12/14/06, Kevin <coscpp@gmail.com> wrote:

I understand now, thank you both of you
dblack@wobblini.net wrote:
> Hi --
>
> On Fri, 15 Dec 2006, Kevin wrote:
>
> > I run one of examples of Programming Ruby, code as follows:
> > ------------
> > class Sone
> > ...
> > end
> >
> > song = Sone.new(.., .., ..)
> > song.inspect
> > song.to_s
> > -----------
> > why I can't see output? where is output of inspect and to_s ?
> > It outputs to somewhere else? IO object ?
>
> inspect and to_s just produce strings. To see them, you have to print
> them :slight_smile: In fact, there are some handy methods for this:
>
> p song # automatically calls inspect
> puts song # automatically calls to_s
>
> Also, if you are working in irb (the interactive Ruby terminal),
> you'll see the value of every expression you type in. So in irb, if
> your expression evaluates to a string, you'll see the string without
> having to explicitly ask for it to be printed.
>
> David
>
> --
> Q. What's a good holiday present for the serious Rails developer?
> A. RUBY FOR RAILS by David A. Black (http://www.manning.com/black\)
> aka The Ruby book for Rails developers!
> Q. Where can I get Ruby/Rails on-site training, consulting, coaching?
> A. Ruby Power and Light, LLC (http://www.rubypal.com)