From: Cameron McBride <cameron.mcbride@...>
Date: 2007-11-21T01:11:16+09:00
Subject: Re: Arrays not working as I expected - help

Hello,

On Nov 20, 2007 11:00 AM,  <rrajeshh@gmail.com> wrote:
> Hi
> I am new programmer to Ruby. Just 1 days old. I do have some
> background in java.
>
> I am having a problem that is troubling me since yesterday and having
> spend several hours on it, I still dont have any idea.
>
> CODE WORKING GREAT BELOW
>
> require 'rubygems'
> require 'hpricot'
> require 'open-uri'
>
>         page = Hpricot(open("http://finance.google.com/finance/historical?
> q=ORCL&histperiod=weekly&start=01&num=2"))
>
>          page.search("#prices").each do |timesection|
>
>         values=timesection.search("td")
>                 datePointValue = {
>                         "date"  => values[0].inner_html,
>                         "open"  => values[1].inner_html,
>                         "high"  => values[2].inner_html,
>                         "low"   => values[3].inner_html,
>                         "close" => values[4].inner_html,
>                         "volume" => values[5].inner_html
>                 }
>
>                 datePointValue.each do |key, value|
>                         puts key + " - " + value
>                 end
>     end
>
>
> But when I add a loop and change the code as follows. It gives me
> error message
> UPDATED CODE - NOT WORKING -
>
>         page = Hpricot(open("http://finance.google.com/finance/historical?
> q=ORCL&histperiod=weekly&start=01&num=1"))
>
>          page.search("#prices").each do |timesection|
>
>         timesection.search("tr").each do |datePointSets|
>                         values = datePointSets.search("td")
>
>                         datePointValue = {
>                                 "date"  => values[0].inner_html,
>                                 "open"  => values[1].inner_html,
>                                 "high"  => values[2].inner_html,
>                                 "low"   => values[3].inner_html,
>                                 "close" => values[4].inner_html,
>                                 "volume" => values[5].inner_html
>                         }
>
>                         datePointValue.each do |key, value|
>                                 puts key + " - " + value
>                         end
>                 end
>     end
>
> ERROR MESSAGE
> htest.rb:14: undefined method `inner_html' for nil:NilClass
> (NoMethodError)
>         from htest.rb:10:in `each'
>         from htest.rb:10
>         from htest.rb:8:in `each'
>         from htest.rb:8
>
> Kindly suggest.

At a knee-jerk guess, you've changed how 'values' is populated.  I'd
wager that the values result from the Hpricot search isn't properly
set.  You should print values before you set the datePointValue hash
and see what it contains.

In addition, you might consider another sanity check if you explicitly
access 6 elements of an array.  Like

raise "Parsing Error: values not set correctly" if (values.nil? or
values.size < 6)

Cheers.

Cameron