Hi,
  I'm tryind to count distinct ids from an array (array_of_ids =
[1,2,3,1,2]), and want a result array of hashes looking like it :
result = [{;id=>1,:count=>2},{;id=>2,:count=>2},{;id=>3,:count=>1}]

i tried it, but it always returns errors :
result = array_of_ids.inject(Array.new){ |a,x| elt = a.find{|h| h[:id]
== x} || {:id => x, :count => 0}; elt[:count] += 1; elt}

i took my information from this post :
http://groups.google.com/group/comp.lang.ruby/browse_thread/thread/3122212f6db8d7f5/04a7b10da8195cec?lnk=gst&q=array++count&rnum=8#04a7b10da8195cec

If someone could help.

regards