From: dblack@...
Date: 2006-04-24T00:20:46+09:00
Subject: Re: how to ensure no blank lines in DATA statements

Hi --

On Mon, 24 Apr 2006, Joseph Paish wrote:

> suppose i have the following piece of code to read some data (input by
> the user) following __END__
>
> while line = DATA.gets
>  one_record = line.chomp!.split
>  # do stuff
>  end
>
>
>
> __END__
>
> bought 2 widgets 17.99
> sold 12 widgets 22.49
>
> bought 11 things 12.99
>
> sold 5 things 10.49
>
>
> as you can see, there is a blank line ahead of the first line of data (i
> don't want that), and there may be one or more blank lines or lines
> containing spaces after the data or even between the lines of data.
>
> i can't control what the user will do here, but i need to take it into
> account.  any suggestions on how to ensure that any line i read contains
> the 4 desired fields and doesn't contain anything else (even 4 blank
> spaces like between the last bought and sold records)?

Here's a nice way to avoid worrying about the spaces, though it may
run aground if you have lines that have non-spaces and are malformed:

require 'scanf'

DATA.scanf("%s%d%s%f") do |action, num, item, price|
   puts "#{action} #{num} #{item} at $#{price}, total $#{price * num}"
end

Output (with your sample):

bought 2 widgets at $17.99, total $35.98
sold 12 widgets at $22.49, total $269.88
bought 11 things at $12.99, total $142.89
sold 5 things at $10.49, total $52.45


David

-- 
David A. Black (dblack@wobblini.net)
Ruby Power and Light, LLC (http://www.rubypowerandlight.com)

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