From: "David A. Black" <dblack@...>
Date: 2009-06-23T00:06:39+09:00
Subject: Re: formatting a listing

Hi --

On Fri, 19 Jun 2009, George George wrote:

>
>
> Thanks a lot Pascal! The code is working though a little complex but a
> very nice learning piece of code. one nitty gritty thing is that not all
> the columns are seperated by a comma. for example your code
>
> File.open("/home/george/test_r.csv",'w') do |f|
> printf "%s\n\n",
> begin
>    matrix = Array.new
>    ncols = 1
>    matrix.push(Array.new)
>    (IO.readlines '/home/george/test.data').
>      map { | line | (line.strip) }.

Don't use the extra parentheses around expressions. They result in
unidiomatic and obfuscated code. They're an artifact of some very
specific disgruntlement about the fact that Ruby differs from Common
Lisp, and they shouldn't be emulated. (Search the ruby-talk archives
for more on this if interested.)

> when given  a file(test.data)  containing
> 1 2
> 2 4
>
> 1 4
> 2 3
>
> 1 3
> 2 3
> 3 5
> 4 6
>
> it produces (test_r.csv)
>
> 1 2,1 4,1 3
> 2 4,2 3,2 3
>   ,   ,3 5
>   ,   ,4 6
>
> which is almost there!
> the ideal output would have been
>
> 1, 2,1, 4,1, 3
> 2, 4,2, 3,2, 3
> ,  ,   ,3, 5
> ,  ,   ,4, 6
>
> Sorry am asking for a horse and the saddle :) what little modification
> should i do to produce the second output?

Could you write an example using letters, instead of digits? I'm
having trouble mapping the input to the output, and having unique
symbols would help.

Judging from the comma count, the last two rows have fewer fields than
the first two. Is that right?


David

-- 
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