Hourly histogram of incoming calls

histogram.py

from datetime import datetime
from datetime import timedelta
diff_time_from_gmt = timedelta(minutes=330)


incoming = []
with open('/home/thej/Desktop/my_incoming_calls.csv', 'rb') as csvfile:
    spamreader = csv.reader(csvfile, delimiter='\t', quotechar='|')
    for row in spamreader:
         incoming.append( ( datetime.strptime(row[4], '%Y-%m-%d %H:%M:%S')+ diff_time_from_gmt ))

pyplot.hist([t.hour + t.minute/60. for t in incoming] , bins=24, facecolor='green', alpha=0.75)
pyplot.xlabel('By Hour')
pyplot.ylabel('Count')
pyplot.title(r'Calls')
pyplot.grid(True)
pyplot.show()