Project 5 Exercise 3

 Exercise 3 - Busiest Hour

import sys
import string
import logging

from util import mapper_logfile
logging.basicConfig(filename=mapper_logfile, format='%(message)s',
                    level=logging.INFO, filemode='w')

def mapper():
    """
    In this exercise, for each turnstile unit, you will determine the date and time 
    (in the span of this data set) at which the most people entered through the unit.
    
    The input to the mapper will be the final Subway-MTA dataset, the same as
    in the previous exercise. You can check out the csv and its structure below:
    https://www.dropbox.com/s/meyki2wl9xfa7yk/turnstile_data_master_with_weather.csv

    For each line, the mapper should return the UNIT, ENTRIESn_hourly, DATEn, and 
    TIMEn columns, separated by tabs. For example:
    'R001\t100000.0\t2011-05-01\t01:00:00'

    Since you are printing the output of your program, printing a debug 
    statement will interfere with the operation of the grader. Instead, 
    use the logging module, which we've configured to log to a file printed 
    when you click "Test Run". For example:
    logging.info("My debugging message")
    """


    for line in sys.stdin:
        data = line.strip().split(",")
        if len(data) == 22 and data[6] == 'ENTRIESn_hourly':
            continue
               
        print "{0}\t{1}\t{2}\t{3}".format(data[1],data[6],data[2],data[3])
        

mapper()

---------------------------------------------------------------------------------------------------------------------

import sys

import logging

from util import reducer_logfile

logging.basicConfig(filename=reducer_logfile, format='%(message)s',

                    level=logging.INFO, filemode='w')

def reducer():

    '''

    Write a reducer that will compute the busiest date and time (that is, the 

    date and time with the most entries) for each turnstile unit. Ties should 

    be broken in favor of datetimes that are later on in the month of May. You 

    may assume that the contents of the reducer will be sorted so that all entries 

    corresponding to a given UNIT will be grouped together.

    

    The reducer should print its output with the UNIT name, the datetime (which 

    is the DATEn followed by the TIMEn column, separated by a single space), and 

    the number of entries at this datetime, separated by tabs.

    For example, the output of the reducer should look like this:

    R001    2011-05-11 17:00:00   31213.0

    R002 2011-05-12 21:00:00   4295.0

    R003 2011-05-05 12:00:00   995.0

    R004 2011-05-12 12:00:00   2318.0

    R005 2011-05-10 12:00:00   2705.0

    R006 2011-05-25 12:00:00   2784.0

    R007 2011-05-10 12:00:00   1763.0

    R008 2011-05-12 12:00:00   1724.0

    R009 2011-05-05 12:00:00   1230.0

    R010 2011-05-09 18:00:00   30916.0

    ...

    ...

    Since you are printing the output of your program, printing a debug 

    statement will interfere with the operation of the grader. Instead, 

    use the logging module, which we've configured to log to a file printed 

    when you click "Test Run". For example:

    logging.info("My debugging message")

    '''

    max_entries = 0.0

    old_key = None

    datetime = ''

    for line in sys.stdin:

        data = line.strip().split('\t')

        if len(data) != 4:

            continue

        this_key, count, date, time  = data

        count = float(count)

        if old_key and old_key != this_key:

            print "{0}\t{1}\t{2}".format(old_key, datetime, max_entries)

            max_entries = 0

            datetime = ''

        old_key = this_key

        if count >= max_entries:

            max_entries = count

            datetime = str(date) + ' ' + str(time)

    if old_key != None:

        print "{0}\t{1}\t{2}".format(old_key, datetime, max_entries)

        logging.info("{0}\t{1}\t{2}".format(old_key, datetime, max_entries))

reducer()