From: Peter Bailey <pbailey@...>
Date: 2009-06-26T03:37:15+09:00
Subject: Re: How do I get an integer from an array?

Brian Candler wrote:
> Alex wrote:
>> The index method of the array class is a method just like any other, so 
>> you
>> could just as well write it like:
>> 
>> foo.[](0).[](0)
>> 
>> which calls the `[]' method on the result of the previous call of the 
>> `[]'
>> method, which is an array.
>> 
>> foo[0] is just a shortcut ruby gives you for calling foo.[](0)
> 
> Or in this particular case, you can do
> 
>   foo.first.first

Well, interestingly, I've succeeded in some of my scripts. But, in this 
one, it fails. It displays a few hundred filenames with page counts, 
but, in this directory, there are literally thousands of PDF files. So, 
it does a bunch, then dies.

Dir.glob("*.pdf").each do |pdffile|
 pages = `pdfinfo #{pdffile}`
 pages = pages.scan(/^Pages:[ ]{2,99}([0-9]+)/)
 pages = pages[0][0].to_i
 puts "#{pdffile}  #{pages}"
end

I get:
================ NoMethodError =====================
C:\Users\pb4072\Documents\scripts\RUBY\multitiffs.rb:8:in `block in 
<main>'
      pages = pages[0][0].to_i
C:\Users\pb4072\Documents\scripts\RUBY\multitiffs.rb:5:in `each'
    Dir.glob("*.pdf").each do |pdffile|
C:\Users\pb4072\Documents\scripts\RUBY\multitiffs.rb:5:in `<main>'
    Dir.glob("*.pdf").each do |pdffile|

=============================================
Exception: undefined method `[]' for nil:NilClass
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