tomlobato

require 'pry' # gem install pry

# Pass in an enumeration of data and
# (optionally) a block to extract the grouping aspect of the data.
#
# Optional: sort_by lambda (operates on group key and count)

def puts_hist(data, sort_by:nil, &blk)
  data   = data.map(&blk) if blk
  counts = data.each_with_object(Hash.new(0)) {|k,h| h[k]+=1}