From: Dark Ambient <sambient@...>
Date: 2006-07-09T22:22:35+09:00
Subject: Re: Sorting arrays

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On 7/8/06, Matthew Smillie <M.B.Smillie@sms.ed.ac.uk> wrote:

> > So, starting off with an empty sorted array, recursive_sort finds the
> > *lowest* element (not the first element) in the unsorted array, adds
> > it to the sorted array, and removes it from the unsorted array.


I'm trying to take this in one step at a time. Only I can't grasp, the
mechanics of the first step. In theory I follow what's supposed to be going
on but that's not helping my understanding. I re-created the first step
slightly and dropped the recursion.

def sort(list)
    sorted = []
    unsorted = []

lowest = nil
   list.each do |item|
      if lowest == nil || item < lowest
         lowest = item
      end
   end

   sorted.push(lowest)
   puts sorted

end
mylist = ['five', 'three', 'one', 'ten', 'eight']
sort mylist

Amazingly :), 'eight' is pushed into the first element of the sorted array.
When I asked some posts back through about the elements being compared to
nil I was told that wasn't the case.  However, lowest is being set to nil.
Then the statement lowest is equal to nil, or item smaller then lowest (or
nil).  I believe nil has a value, which is 0 or false.  However how can any
item be smaller then it.  Bottom line is I'm not seeing the magic here in
the comparison to find the correct element.
My apologies for my density with this code.

Stuart

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