Exercise 8-14 Gas Prices: Average Price Per Month
# The get_price function accepts a string that is assumed to be
# in the format MM-DD-YYYY:Price. It returns the Price component
# as a float.
def get_price(str):
# Split the string at the colon.
items = str.split(‘:’)
# Return the price, as a float.
return float(items[1])
# The get_month function accepts a string that is assumed to be
# in the format MM-DD-YYYY:Price. It returns the MM component
# as an int.
def get_month(str):
# Split the string at the hyphens.
items = str.split(‘-‘)
# Return the month, as an int.
return int(items[0])
# The get_day function accepts a string that is assumed to be
# in the format MM-DD-YYYY:Price. It returns the DD component
# as an int.
def get_day(str):
# Split the string at the hyphens.
items = str.split(‘-‘)
# Return the day, as an int.
return int(items[1])
# The get_year function accepts a string that is assumed to be
# in the format MM-DD-YYYY:Price. It returns the YYYY component
# as an int.
def get_year(str):
# Split the string at the colon.
items = str.split(‘:’)
# Split the date item at the hyphens.
date_items = items[0].split(‘-‘)
# Return the year, as an int.
return int(date_items[2])
# The display_monthly_averages function steps through the gas_list
# list, calculating and displaying the average price for each month.
def display_monthly_averages(gas_list):
month_names = [‘January’, ‘February’, ‘March’, ‘April’, ‘May’,
‘June’, ‘July’, ‘August’, ‘September’, ‘October’,
‘November’, ‘December’]
current_month = get_month(gas_list[0])
current_year = get_year(gas_list[0])
total = 0
count = 0
average = 0
# Step through the list.
for e in gas_list:
if (get_month(e) == current_month) and (get_year(e) == current_year):
total += get_price(e)
count += 1
else:
average = total / count
print(‘Average price for ‘, month_names[current_month-1],
‘, ‘, current_year, ‘: $’,
format(average, ‘.2f’), sep=”)
current_month = get_month(e)
current_year = get_year(e)
total = 0
count = 0
# Display the average for the last month.
print(‘Average price for ‘, month_names[current_month-1],
‘, ‘, current_year, ‘: $’,
format(average, ‘.2f’), sep=”)
def main():
# Open the file.
gas_file = open(‘GasPrices.txt’, ‘r’)
# Read the file’s contents into a list.
gas_list = gas_file.readlines()
# Display the monthly average prices.
display_monthly_averages(gas_list)
main()