From: Sander Land <sander.land@...>
Date: 2006-10-06T06:31:48+09:00
Subject: Re: 1st program -- how would you improve this?

On 10/5/06, Esmail Bonakdarian <ebonakDUH@hotmail.com> wrote:
> Hi,
>
> I just wrote my first Ruby program and I would be very interested in
> some feedback as to style and how to write things more in the
> Ruby-way.
>
> I know I could use more methods and/or possibly classes, and that
> will happen, but for now I would like to hear what betrays my
> programming style coming from other languages.
>
> Thanks,
> Esmail
> ...
> Works .. but it's not pretty, at least in terms of lack of methods
> etc. Other ways to improve this?

Hi Esmail,

Here's my shot at rewriting your program.
Note that this is simply how I would write it, not everything changed
is necessarily an 'improvement'.

require 'open-uri'
def random_date(years_back=5)
  Time.at(Time.now - rand(years_back * 365 * 24 * 3600)).strftime('%y%m%d')
end

r_date=random_date(10)
puts r_date

open("http://antwrp.gsfc.nasa.gov/apod/ap#{r_date}.html") {|f|
  text = f.read
  if text =~ /<TITLE>([^<]*)/i
   puts "----------------------------------------------"
   puts $1.strip
   puts "----------------------------------------------\n\n"
  end

  if text =~ /href=\"([^\"]+(jpg|gif))\">/i
    image = $1
    fetch_url = "http://apod.nasa.gov/apod/" + image
    puts fetch_url
    # system(...)
  end
}

Comments:

- your random_date generated invalid dates sometimes, 01/30/02 and
such. Using timestamps for everything is a bit more stable (Although
slightly off if lots of leap years are in the range).
- puts does to_s automatically,  so printf("%s\n",..) is never needed
- reading the text per line was meant as an optimization? This is
probably not necessary.
- $' / $` and such are rarely used in Ruby, try to avoid them when the
more readable $1 or String#scan will do.
- more methods / classes are not really needed for such a small program.