From: Daniel Schierbeck <daniel.schierbeck@...>
Date: 2006-08-09T04:25:09+09:00
Subject: Re: Simple looping question

Aqua Fina wrote:
> I have some data in a YAML file that looks like:
> 
> 20060712: [9.174, 131452]
> 20060719: [9.466, 131805]
> 20060727: [9.197, 132150]
> 20060807: [9.778, 132540]
> 
> It represents dates, gallons of gas, and mileage, respectively.
> 
> I want to loop through and print out something like:
> 
> The W gallons of gas purchased on X lasted Y days. The mileage was Z 
> miles per gallon.
> 
> What is the best way to do this? I need the next date from the next 
> entry in the hash, so a simple .each won't work. I can't quite wrap my 
> head around this problem.

You'll need to figure out how to compare two dates, but I'm sure one of 
the core classes has a way of accomplishing that. As for knowing which 
date is next:

   entries = hash.entries.sort_by{|date, *| date }
   entries.each_with_index do |entry, i|
     if i < entries.length
       days = do_comparison(entry[0], entries[i + 1])
       ...
     end
   end


Cheers,
Daniel