alphasights.rb

#
# input:
#
# >> log
# => [{:time=>201201, :x=>2}, {:time=>201201, :y=>7}, {:time=>201201, :z=>2}, {:time=>201202, :a=>3}, {:time=>201202, :b=>4}, {:time=>201202, :c=>0}]
#

result = {}
log.each do |line|
  result[line[:time]] = result[line[:time]].nil? ? line : result[line[:time]].merge(line)
end
result.values

#
# output:
#
# >> result
# => {201201=>{:time=>201201, :x=>2, :y=>7, :z=>2}, 201202=>{:time=>201202, :a=>3, :b=>4, :c=>0}}
#
# >> result.values 
# => [{:time=>201201, :x=>2, :y=>7, :z=>2}, {:time=>201202, :a=>3, :b=>4, :c=>0}]
#