From: Tim Hunter <TimHunter@...>
Date: 2008-12-31T06:17:01+09:00
Subject: Re: Ruby Noobie needs some help

r wrote:
> Hello,
> I am coming from the python world and trying to learn ruby. Why does
> this throw an error?
> 
> #testscript.rb
> cams = ['cam1', 'cam2', 'cam3']
> def function(s)
>     puts s
>     for x in cams
>         print x
>     end
> end
> test()
> 
> In python this is perfectly valid, must i write a class for
> everything? 

No. Here's the Ruby version:

$cams = ['cam1', 'cam2', 'cam3']
def test(s)
   puts s
   $cams.each {|x| print x}
end

test("hello!")

I made a couple of assumptions about your program, namely that you 
intended to name the function "test", not "function", and that you 
intended to pass it an argument. If you want to define test such that it 
can take an argument or not, then you could define it with a default 
argument like this:

def test(s=nil)
    puts s
    $cams.each {|x| print x}
end

Note that in Ruby global variables are declared with a $ prefix.

Also how does ruby handle modules compared to python? In
> python i can do "import testscript" and access the function and array
> as...
> py> testscript.function('hello')
> py> testscript.cams[0]
> 
> I can also do "from testscript import cams, function" and then do
> py> cams[0]
> py> function('hello')
> 

Ruby has the "require" statement. I don't know enough Python to tell you 
how different it is from import.

-- 
RMagick: http://rmagick.rubyforge.org/