From: Morton Goldberg <m_goldberg@...>
Date: 2006-11-21T14:03:50+09:00
Subject: Re: Using two justifications on the same line.


On Nov 20, 2006, at 6:07 PM, Shiloh Madsen wrote:

> Ok, so the chapter I am working on now is asking for me to write a
> table of contents with the title left justified and the pages right
> justified. I did this much earlier in the book with individual lines,
> and it came out fine. The code I used initially was :
>
> line_width = 60
> puts ("Chapter 1: Getting Started".ljust(line_width/2) + "page
> 1".rjust(line_width/2))
> puts ("Chapter 2: Numbers".ljust(line_width/2) + "page 9".rjust 
> (line_width/2))
> puts ("Chapter 3: Letters".ljust(line_width/2) + "page 13".rjust 
> (line_width/2))
>
> The chapter I am reading now is about arrays, so I am supposed to load
> the same data into an array and accomplish the same task. What Ive
> tried is several variations on this:
>
> chapters = ['Chapter 1: Getting started','Chapter 2: Numbers',
> 'Chapter 3: Letters']
> pages = ['page 1','page 9', 'page 13']
> line_width = 60
> puts (chapters.ljust(line_width/2) + pages.rjust(line_width/2))
>
> ...with the last line having changed a number of times. Obviously, I
> haven't been able to get the code to run right. Could anyone tell me
> what I am missing?\

The problem is that an array doesn't respond to either ljust or  
rjust. You need to extract the strings from their containing arrays.  
Also, it's easier to use one array than two, so I recommend something  
like:

source = [
    'Chapter 1: Getting started',
    'page 1',
    'Chapter 2: Numbers',
    'page 9',
    'Chapter 3: Letters',
    'page 13'
]
line_width = 60
until source.empty?
    chapter = source.shift
    page = source.shift
    puts chapter.ljust(line_width/2) + page.rjust(line_width/2)
end

Regards, Morton