From: "Kroeger, Simon (ext)" <simon.kroeger.ext@...>
Date: 2006-01-31T22:05:11+09:00
Subject: Re: Loop weirdness


> > def categorise(items)
> >    items.inject([]) do |a, item|
> >      ary = a.assoc(item[:num]) || (a << [item[:num], []]).last
> >      ary.last << item[:foo]; a
> >    end.map{|k, v| {:num => k, :items => v}}
> > end
> 
> That's pretty slick :). One question though:
> 
> The docs say Array#map only yeilds on value: the value of the item in
> the array. However, you are using two in your block. I 
> understand (from
> looking at the code), that this assigns each value in the 
> item array to
> k and v respectively, but how does that work? Is there any docs about
> that anywhere?

that's the way multiple assignement works in ruby

a, b = 1, 2

a, b = [1, 2]

is equivalent (at least for this purpose).

map yields arrays of two elements in this case and I'm assigning them to
two variables.

cheers

Simon