From: Logan Capaldo <logancapaldo@...>
Date: 2006-03-04T08:19:19+09:00
Subject: Re: Python for Ruby programmers


On Mar 3, 2006, at 5:47 PM, Joe Van Dyk wrote:

> On 3/3/06, Joe Van Dyk <joevandyk@gmail.com> wrote:
>> Hi,
>>
>> I need to write a GUI for a vanilla RHEL3 box (with no extra software
>> installed on it).  I figure Python / pygtk2 is a good choice for  
>> this,
>> as it's installed by default.  (Ruby is 1.6.8 on that box, and
>> ruby-gnome2 isn't installed).  The GUI will do various RPM-related
>> things -- it's a program that will examine a machine's configuration
>> and figure out what additional RPMs need to be installed before a  
>> user
>> can run our software.
>>
>> I don't know much python, although I did write a small program in  
>> it a
>> few years ago.  Any pointers on where I could get a quick  
>> introduction
>> to it?  I don't need an introduction to programming, I need an
>> introduction to Python (and preferably from a Rubyist POV).
>
> What's the Ruby equivalent of this?
>
> for f in filter(lambda f: f(-1)>=f(1),
>                 [lambda x:x, lambda x:x**2, lambda x:x**3]):
>     for x in range(-10, 11):
>         print x, f(x)
>

Well after struggling with mapping the results of the code to the  
meaning I came up with this, which is pretty much a "word-for-word"  
translation to ruby:

[ lambda { |x| x }, lambda { |x| x**2 }, lambda { |x| x**3 }].select  
{ |f| f.call(-1) >= f.call(1) }.each do |f|
    (-10...11).each do |x|
         puts "#{x} #{f.call(x)}"
     end
end