From: William James <w_a_x_man@...>
Date: 2009-03-01T07:59:10+09:00
Subject: Re: How to put multiple values into a variable.

Pascal J. Bourguignon wrote:

> Harry Nash <hjnash@adistantstar.com> writes:
> 
> > I am new to coding, I have tried to place a number of data strings into
> > one variable 
> 
> This is not possible.  By definition a variable has only one value.
> This is not quantic computing.
> 
> What you could do is to put the values in some object, and put that
> object in the variable.  You may choose between a custom object, a
> hash-table, an array, a list, etc.  For example:
> 
> filename = "/tmp/example.mp3"
> mp3_title = "Example"
> mp3_artist = "Musician" 
> 
> file_link = [ Dir.pwd, filename, mp3_title, mp3_artist ]

file_link =  Dir.pwd, filename, mp3_title, mp3_artist

> file_link[0]
> file_link[1]
> 
> file_link = { :directory => Dir.pwd, 
>               :file      => filename, 
>               :title     => mp3_title,
>               :artist    => mp3_artist }


file_link = { :directory, Dir.pwd,
              :file   , filename, 
              :title  , mp3_title,
              :artist , mp3_artist }


> file_link[:directory]
> file_link[:file]
> 
> class Cons 
>   attr_accessor :first,:rest
> 
>   def initialize(f,r)
>      @first=f
>      @rest=r
>   end
> 
>   def Cons.list(*objects)
>      result = nil
>      objects . reverse . each { | object | result = Cons.new(object,result) }
>      result
>   end


def foo *objects
  objects
end
    ==>nil
foo( 2, 4, 9 )
    ==>[2, 4, 9]


> 
>   # ...
> 
> end
> 
> file_link = Cons.list( Dir.pwd, filename, mp3_title, mp3_artist )
> file_link . first
> file_link . rest . first
> 
> 
> > but I am missing something in the format. See example
> > below.
> 
> What format?  Are you speaking of the syntax of the language, or do
> you want to format a string?  I ask because the expression you show us
> is not even syntactically valid...
> 
> 
> > Note each part of the line after = does have a real value, 
> > I just can't format the string.
> > 
> > file-link = Dir.pwd, "#{filename}", "#{mp3-title}", "#{mp3-artist}"
> 
> So, assuming you want to build a new string formated with these
> elements, separated by commas, you can do that with sprintf:
> 
> file_link = sprintf("%s, %s, %s, %s", Dir.pwd, filename, mp3_title, mp3_artist )


file_link = [Dir.pwd, filename, mp3_title, mp3_artist].join(", ")

> 
> If you have several lines to format, you may want to specify column widths:
> 
> file_link = sprintf("%-20s, %-20s, %-30s, %s", Dir.pwd, filename, mp3_title, mp3_artist )