From: Johan Veenstra <johan.veenstra@...>
Date: 2006-01-29T22:06:24+09:00
Subject: Re: Loop weirdness

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Hmm interesting, I've added line number, couldn't explain it other wise:

def categorise(items)
 1  categorised =3D []
 2  add =3D proc { |item| categorised << { :num =3D> item[:num], :items =3D=
> [
item[:foo] ] } }
 3  items.each do |item|
 4    if categorised.empty?
 5      add.call(item)
 6    else
 7      categorised.each do |cat|
 8        if cat[:num] =3D=3D item[:num]
 9          cat[:items] << item[:foo]
10          break
11        elsif cat =3D=3D categorised.last
12          add.call(item)
13        end
14      end
15    end
16  end
17  categorised
end

p categorise( [ { :num =3D> 1, :foo =3D> 'foo1' }, { :num =3D> 45, :foo =3D=
> 'foo45'
} ] )

1: categorised =3D []
3: first item( item[:num] =3D=3D 1 )
4: categorised is empty
5: {:num=3D>1, :items=3D>["foo1"]} is added to categorised, so far so good
3: next item( item[:num] =3D 45 )
4: categorised is not empty
7: first category (cat[:num] =3D=3D 1)
8: item[:num] is not equal to cat[:num] (45 !=3D 1 )
11: cat is last category
12: { :num =3D> 45, :foo =3D> ['foo45'] } is added to categorised, just wha=
t we
need
7: next category (yes there is a next category, number 45 that we've just
added a moment ago) ( cat[:num] =3D=3D 45)
8: added ['foo45'] to category 45, oh boy
10:break
3: no more items
18: return categorised

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