From: Alex <imphasing@...>
Date: 2009-06-25T03:25:42+09:00
Subject: Re: How do I get an integer from an array?

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On Wed, Jun 24, 2009 at 2:18 PM, Peter Bailey <pbailey@bna.com> wrote:

> Roger Pack wrote:
> > Peter Bailey wrote:
> >> Yes, if it do pages.to_s, I get [["78"]].
> >
> > Looks like you want pages[0][0].to_i or what not then.
> > =r
>
> Yup. That did it. Thank you very much, Roger. Now, I have to admit, I've
> never, ever seen that double array counter notation. [0][0]. That's
> totally weird to me. But, it works!
>
> Dir.chdir("N:/infoconpdf")
> file = "ehs-X7917735.pdf"
> pages = `pdfinfo #{file}`
> pages = pages.scan(/^Pages:[ ]{2,99}([0-9]+)/)
> pages = pages[0][0].to_i
> 1.upto(pages) do |n|
>  puts n
> end
>
> I got:
> 1
> 2
> 3
> 4
> 5
> 6
> 7...
> 78
> --
> Posted via http://www.ruby-forum.com/.
>

The double notation works just like chaining any other methods together, IE

foo = bar.method.method

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)



Alex

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