From: Julian Gall <julian.gall@...>
Date: 2006-03-04T03:12:45+09:00
Subject: Re: Array comparison returning nil

Stephen Waits wrote:
> Maybe you could post an irb session of your own so we could see
> what's happening?

Not really possible. I am writing a Rails application with a sortable 
list on a web page. An XML_Http_request serialises the ids of the list 
items and POSTs them to my action controller. By the time I see this 
data it is an array of identifiers (numbers) in params[:itemlist].

I extract this to a local array with:

    new_item_ids = []
    params[:itemlist].each {|item| new_item_ids << item}

I want to compare this with another local array of my original 
(unsorted) identifiers. i.e.

    original_item_ids.sort <=> new_item_ids.sort

This doesn't work, although this does:

    original_item_ids.sort.join('-') == new_item_ids.sort.join('-')

It is odd that join works to produce the expected string where <=> 
thinks it has a problem.

Julian

-- 
Posted via http://www.ruby-forum.com/.