solution to convert place hours of operation from google place details api to a human readable format.

gistfile1.rb

# the data we get from google looks like:
# - close:
#     day: 0
#     time: '1700'
#   open:
#     day: 0
#     time: '1000'
# - close:
#     day: 3
#     time: '1700'
#   open:
#     day: 3
#     time: '1000'
# - close:
#     day: 4
#     time: '1700'
#   open:
#     day: 4
#     time: '1000'
# - close:
#     day: 5
#     time: '1700'
#   open:
#     day: 5
#     time: '1000'
# - close:
#     day: 6
#     time: '1700'
#   open:
#     day: 6
#     time: '1000'

# and we need to be able to display it as:
#   Wed-Sun : 10am - 5pm
#   - or - 
#   Mon,Wed,Fri : 8am - 7pm
#   Tue,Thur : 10am - 11pm
#   - or -
#   Mon - Fri : 10am - 2pm, 4pm - 8pm

# easiest way to test this is to load the functions below into a rails console, then copy and paste the one of the following:
# helper.operating_hours({"periods" => [{"close" => {"day" => 0,"time" => "1700"},"open" => {"day" => 0,"time" => "1000"}},{"close" => {"day" => 3,"time" => "1700"},"open" => {"day" => 3,"time" => "1000"}},{"close" => {"day" => 4,"time" => "1700"},"open" => {"day" => 4,"time" => "1000"}},{"close" => {"day" => 5,"time" => "1700"},"open" => {"day" => 5,"time" => "1000"}},{"close" => {"day" => 6,"time" => "1700"},"open" => {"day" => 6,"time" => "1000"}}]}["periods"])
# helper.operating_hours({"periods" => [{"close" => {"day" => 0,"time" => "1700"},"open" => {"day" => 0,"time" => "1000"}},{"close" => {"day" => 2,"time" => "1700"},"open" => {"day" => 2,"time" => "1000"}},{"close" => {"day" => 4,"time" => "1700"},"open" => {"day" => 4,"time" => "1000"}},{"close" => {"day" => 5,"time" => "1700"},"open" => {"day" => 5,"time" => "1000"}},{"close" => {"day" => 6,"time" => "1700"},"open" => {"day" => 6,"time" => "1000"}}]}["periods"])
# helper.operating_hours({"periods" => [{"close" => {"day" => 0,"time" => "1700"},"open" => {"day" => 0,"time" => "1000"}},{"close" => {"day" => 2,"time" => "1700"},"open" => {"day" => 2,"time" => "1000"}},{"close" => {"day" => 4,"time" => "1915"},"open" => {"day" => 4,"time" => "1000"}},{"close" => {"day" => 5,"time" => "1700"},"open" => {"day" => 5,"time" => "1000"}},{"close" => {"day" => 6,"time" => "1700"},"open" => {"day" => 6,"time" => "1000"}}]}["periods"])
# helper.operating_hours({"periods" => [{"close" => {"day" => 0,"time" => "1700"},"open" => {"day" => 0,"time" => "1000"}},{"close" => {"day" => 2,"time" => "1700"},"open" => {"day" => 2,"time" => "1000"}},{"close" => {"day" => 4,"time" => "1915"},"open" => {"day" => 4,"time" => "1000"}},{"close" => {"day" => 5,"time" => "1700"},"open" => {"day" => 5,"time" => "1000"}}]}["periods"])
# helper.operating_hours({"periods" => [{"close" => {"day" => 0,"time" => "1700"},"open" => {"day" => 0,"time" => "1000"}},{"close" => {"day" => 1,"time" => "1700"},"open" => {"day" => 1,"time" => "1000"}},{"close" => {"day" => 4,"time" => "1700"},"open" => {"day" => 4,"time" => "1000"}},{"close" => {"day" => 5,"time" => "1700"},"open" => {"day" => 5,"time" => "1000"}}]}["periods"])
# helper.operating_hours({"periods" => [{"close" => {"day" => 0,"time" => "1400"},"open" => {"day" => 0,"time" => "1000"}},{"close" => {"day" => 0,"time" => "1900"},"open" => {"day" => 0,"time" => "1700"}},{"close" => {"day" => 1,"time" => "1400"},"open" => {"day" => 1,"time" => "1000"}},{"close" => {"day" => 1,"time" => "1900"},"open" => {"day" => 1,"time" => "1700"}},{"close" => {"day" => 2,"time" => "1400"},"open" => {"day" => 2,"time" => "1000"}},{"close" => {"day" => 2,"time" => "1900"},"open" => {"day" => 2,"time" => "1700"}},{"close" => {"day" => 3,"time" => "1400"},"open" => {"day" => 3,"time" => "1000"}},{"close" => {"day" => 3,"time" => "1900"},"open" => {"day" => 3,"time" => "1700"}},{"close" => {"day" => 4,"time" => "1400"},"open" => {"day" => 4,"time" => "1000"}},{"close" => {"day" => 4,"time" => "1900"},"open" => {"day" => 4,"time" => "1700"}},{"close" => {"day" => 5,"time" => "1400"},"open" => {"day" => 5,"time" => "1000"}},{"close" => {"day" => 5,"time" => "1900"},"open" => {"day" => 5,"time" => "1700"}},{"close" => {"day" => 6,"time" => "1400"},"open" => {"day" => 6,"time" => "1000"}},{"close" => {"day" => 6,"time" => "1900"},"open" => {"day" => 6,"time" => "1700"}}]}["periods"])  
  
# convert place hours data from google into a displayable format
# [{"close" => {"day" => 0,"time" => "1700"},"open" => {"day" => 0,"time" => "1000"}}] = { "Sun" => "10am - 5pm"}
def operating_hours(periods)
  # group similar periods together in a hash
  # key = formatted time (open - close)
  # value = array of days (as digits)
  hours_of_op = periods.inject({}) { |memo, period|
    time = format_time(period)
    (memo[time] ||= []) << period["open"]["day"]; memo
  }

  # now that our hash's values are an array of day digits,
  # convert that array into a readable string
  hours_of_op = hours_of_op.reduce({}) { |memo, (key, value)|
    memo[key] = format_days(value); memo
  }

  # displaying the data will be grouped by similar days, then hours.
  # right now, our data strucutre is organized by the hours, so we need
  # to do an invert/combine while ensuring we preserve each time span.
  # this is primarily for those hours of operations that have breaks
  # (i.e. siestas). as our structure is now, we'd have to say:
  # Mon - Fri : 10, 2, Mon - Fri : 4 - 8.
  # with this invert/combine, we'll be able to say:
  # Mon - Fri : 10-2, 4-8.
  hours_of_op = hours_of_op.reduce({}) { |memo,(key,value)|
    (memo[value] ||=[]) << key; memo
  }.reduce({}) { |memo, (key,value)|
    memo[key] = value.join(', '); memo
  }
end

# convert 24h span ( 1000 - 1700 ) to 12h span ( 10am - 5pm )
def format_time(val)
  [val["open"]["time"], val["close"]["time"]].inject([]) { |memo, time|
    memo << Time.strptime(time, "%H%M").strftime("%l:%M%P").gsub(/:00/, '').strip
    memo
  }.join(' - ')
end

# take day digits and turn them into day words,
# while combining consecutive days into spans,
def format_days(open_days)
  days_array = %w[Sun Mon Tue Wed Thur Fri Sat]

  # group by consecutive days
  prev = open_days[0]
  consecutive_groups = open_days.slice_before { |cur|
    prev, prev2 = cur, prev
    prev2 + 1 != prev
  }.to_a

  # if a place is closed in the middle of the week, but open on sunday and saturday,
  # bring the sunday group around to the last group
  # so instead of "Sun, Mon, Wed-Sat", you'll have "Wed-Mon"
  if consecutive_groups.length > 1 and consecutive_groups.first.first == 0 and consecutive_groups.last.last == 6
    consecutive_groups.last.concat(consecutive_groups.delete(consecutive_groups.first))
  end

  # convert day digits into day words, creating spans where appropriate
  consecutive_groups.map! { |range|
    range.map! { |parts| days_array[parts] }
    range.length <= 2 ? range.join(', ') : "#{range.first} - #{range.last}"
  }.join(', ')
end