Using the p command to print files

ruby-talk
1

If any one has a copy of "why's poignant guide to ruby", turn to page 45. I can see immediately that
i)`ruby p Dir ['*']` works and lists all files within a specified directory. However
ii)`ruby p File::methods` produces the error..."ruby: No such file or directory -- p (LoadError)"
Is ii) just a way to show the generic syntax of the command?

···

--
John Maclean
MSc (DIC)
07739 171 531

2

[John Maclean <info@jayeola.org>, 2006-01-02 04.42 CET]

If any one has a copy of "why's poignant guide to ruby", turn to page 45. I can see immediately that
i)`ruby p Dir ['*']` works and lists all files within a specified directory. However
ii)`ruby p File::methods` produces the error..."ruby: No such file or directory -- p (LoadError)"
Is ii) just a way to show the generic syntax of the command?

The examples given are:

i) p Dir['idea-*.txt']

ii) p File::methods

(there are no "ruby" or backticks). You should try them on an irb shell, or
writing them on a file and then running it with "ruby file", or passing them
as a parameter to ruby, after the parameter "-e", so:

  ruby -e "p Dir['idea-*.txt']"

  ruby -e "p File::methods"

It's best to do that only if you understand how your command shell
interprets quotes.

Good luck.

···

I downloaded the PDF file and didn't find what you wrote on page 45, only something like it on page 35. Next time please try to find the relevant html page (it is a little upwards from <http://poignantguide.net/ruby/chapter-4.html#section4&gt;\).

3

ii) just a way to show the generic syntax of the command?

If you've done a full Ruby install, you should have the ri command at your disposal:

Example usage:
   ri Object
   ri Object::new
   ri Kernel#p

-Ben

4

~/Desktop/ruby-1.8.4%> ri Object::new
------------------------------------------------------------ Object::new
     Object::new()

···

Benjamin Stiglitz <ben@tanjero.com> wrote:

   ri Object::new

------------------------------------------------------------------------
     Not documented
~/Desktop/ruby-1.8.4%> ri Kernel#p
zsh: no matches found: Kernel#p

just for fun )))
--
une bévue

5

(~/):~>$: ri "Kernel#p"

--------------------------------------------------------------- Kernel#p
      p(obj, ...) => nil

···

On Jan 1, 2006, at 11:27 PM, Une bévue wrote:

Benjamin Stiglitz <ben@tanjero.com> wrote:

   ri Object::new

~/Desktop/ruby-1.8.4%> ri Object::new
------------------------------------------------------------ Object::new
     Object::new()
------------------------------------------------------------------------
     Not documented
~/Desktop/ruby-1.8.4%> ri Kernel#p
zsh: no matches found: Kernel#p

just for fun )))
--
une bévue

------------------------------------------------------------------------
      For each object, directly writes obj.inspect followed by the
      current output record separator to the program's standard output.
      p bypasses the Ruby I/O libraries.

         S = Struct.new(:name, :state)
         s = S['dave', 'TX']
         p s

      produces:

         #<S name="dave", state="TX">

you need to quote it because of the # char

Cheers-
Ezra

6

fine, thanks, i got it :wink:

···

Ezra Zygmuntowicz <ezmobius@gmail.com> wrote:

you need to quote it because of the # char

--
une bévue