Have you ever have to iterate over an array from say the params hash? You probably have added some code to make sure that data exists in the hash element first before doing the loop. This is a cool little trick to help condense some code. Normally I would write this:
if params[:accounts] and params[:accounts].size > 0
params[:accounts].each do |account|
# Do something with account here
end
end
As you can see, kind of ugly. Here is the change:
(params[:accounts] || []).each do |account| # Do something with account end
AHH!!! Much nicer!