From: Matthew Bennett <matthew@...>
Date: 2009-07-12T01:21:50+09:00
Subject: Re: one line sorting

Haris Bogdanovi� wrote:
> Hi.
>
> I would like to implement a sorting algorithm in one line of code if 
> possible.
>
> n=[7,4,9,55,98,11,42]
> n.inject(n[0]) {|min, i| min=i if i<min; min}
>   
Do you actually need to implement the specific algorithm? [2,3,1].sort 
will sort it quite efficiently, or .sort! which will replace the array 
with the sorted version, and you can pass it a block to tell it what 
should be classed as "bigger", so that

[2,3,1].sort { |a, b| b <=> a }

would give equivalent results to

[2,3,1].sort.reverse

If you do need to implement that exact algorithm, my best guess is 
something along the lines of

q = [7,4,9,55,98,11,42]
a = [];
until q.empty? ; a << q.delete(q.min) ; end

There's probably a better way though (there always is!) Array#min is a 
method of Enumerable.
> The result is a number object. Where do I (in general) put a dot in above 
> expression to perform some methods on that object (when expression has a 
> block {} of code in itself ) ?
>   
You can put it at the end of the block, ruby's nice like that. So you 
could do:

[2,3,1].sort { |a, b| a <=> b }.reverse

Regards,
Matthew

PS: Haris pipped me to the post! Still, this might be useful anyway...