Help with a python code

Question

I'm reading this python book called "Python for software design" and it has the following exercise:

Suppose the cover price of a book is 24ドル.95, but the bookstores get a 40% discount. Shipping costs 3ドル for the first copy and 75 cents for each additional copy. What is the total wholesale cost for 60 copies

ok, i have the following code:

bookPrice = 24.95
discount = .60
shippingPriceRest = .75
shippingPriceFirst = 3.00
totalUnits = 60
bookDiscountAmount = bookPrice * discount * totalUnits
shipping = shippingPriceRest * 59 + shippingPriceFirst
result = bookDiscountAmount + shipping
print 'The total price for 60 books including shipping and discount is: '
print 'Total price of the books is: ' + str(bookDiscountAmount)
print 'Total Shipping is: ' + str(shipping)
print 'The Total price is: ' + str(result)

With that I get the following results:

• The total price for 60 books including shipping and discount is:
• Total price of the books is: 898.2
• Total Shipping is: 47.25

• The Total price is: 945.45

• My questions are:

  • Is this correct?
  • How can i make this code better?

• Felix Kling: It's more about basic math than Python...
• philops: yes I'm trying to learn syntax, variables and how to approach them.
• Chang Peng: One suggestion: don't use floating points with money. Record all the prices in cents. Do all the calculations with cents. Convert to dollars when you output.
• philops: yes I'm reading that floating points are not very precise

Answer 1

There are only three things to change:

1) You duplicated the number of books: 60 and 59 both appear in the code. You shouldn't have 59 in there.

2) Print you results like this: print 'The total price is: %.2f' % result

3) Usual Python convention is to name variables_like_this, notLikeThis.

• philops: so a good way would be to do the following? shipping = shippingPriceRest * totalUnits - 1 + shippingPriceFirst
• Ned Batchelder: If you try that, you'll see you need to include some parens to get it to evaluate the way you meant.

Answer 2

The only improvement I would suggest is to use the format-function instead of string concatenation:

print """The total price for {0:d} books including shipping and discount is: 
 Total price of the books is: {1:7.2f} 
 Total Shipping is: {2:7.2f} 
 The Total price is: {3:7.2f}""".format(totalUnits, bookDiscountAmount
 shipping, result)

this makes all the numbers nicely aligned and equally formatted (with two digits after the decimal-point and a total precision of 7).

Edit: And of course, as the other pointed out, don't hard-code the 59 there.

Answer 3

It looks right to me. I would avoid hard-coding 59. Instead, check whether the total is more than one, and divide up as appropriate.

Also, this is minor, but bookDiscountAmount should be bookDiscountedAmount (the discount is the amount they save, not the amount they pay). Other people have pointed out how to improve the string printing.

• philops: yeah, sorry, english is not my mother tongue, thanks for the heads up

Answer 4

i did it this way but i still believe that with a function as above would be better

price = 24.95
discount = price * (40/100)
d_price = price - discount
shipping = 3 + (0.75 * (60 - 1))
wholesale = d_price * 60 + shipping

Answer 5

Please try this:

bookCost = 24.95
numBooks = 60.0
def cost(numBooks):
 bulkBookCost = ((bookCost * 0.60) * numBooks)
 shippingCost = (3.0 + (0.75 * (numBooks - 1)))
 totalCost = bulkBookCost + shippingCost
 print 'The total cost is: $', totalCost
cost(numBooks)

Answer 6

'''Suppose the cover price of a book is 24ドル.95, but bookstores get a 40%
discount. Shipping costs 3ドル for the first copy and 75 cents for each
additional copy. What is the total wholesale cost for
60 copies?
'''
import math
book_price = float(24.95)
discount = float(book_price * 40 /100)
Book_Price= float(book_price - discount)
print ('Book Price is without shipping charges = ' , Book_Price)
shipping = 3.0
Total_Price = float(Book_Price + shipping)
print ('The book 1st price is =' ,Total_Price)
Quantity = int(input('Enter the Number of Copies = '))
if Quantity > 1:
 Price = float(Book_Price * Quantity)
 Additional_copy_price = 0.75
 Q = float(Quantity * Additional_copy_price) 
 Final_Price = float(Price + Q + 3 - .75)
 print (' Final price for more than one copy is = ' , Final_Price)
else:
 print (Total_Price)

Answer 7

cov_price = 24.95 #cost of one book
discount = 0.4
per_one = (cov_price-(cov_price*discount)) #cost of one book on discount
ship_cost = 3 #shipment on first book
other_ship = 0.75 #shipment on other books
purchased = input("Enter number of books purchased : ")
purchased = int(purchased)
if(purchased):
 cost = ((other_ship*(purchased-1)+(per_one*(purchased-1))) + (per_one+3))
 print("The cost of books purchased including discount = ",cost)
 print("Price per one is =",per_one)

i'm a beginner to python and this worked fine for me

Answer 8

 bc = 24.95 #book cost real price
dis = 0.40 # discount percent
bcd = bc*dis # discount amount
bp = bc - bcd # book price
scf = 3 # shipping cost for the first book
scr = 0.75 # shipping cost for the rest books
cost1 = bp*scf
cost2 = bp*scr*59
TotalCost = cost1 + cost2
print(TotalCost)

• user254694: you should probably describe how the code is better than what came before, also the original question asked if it was correct.

Answer 9

This is my basic solution to this problem

price = 24.95 - (24.95)*4/10
order = 60
shipping = 3 + 0.75*(order-1)
print('The total price for 60 books including shipping and discount is %.2f$' % (order*price + shipping))

Answer 10

n = int(input('Enter the number of copies : '))
Book_store_price_of_one_copy = (60*24.95)/100
Shipping_cost_for_copy = (3+((n-1)*0.75))
whole_sale = (n*Book_store_price_of_one_copy)+Shipping_cost_for_copy
print(f'Whole sale of {n} copies is {whole_sale}')

• Bagle: Hi, and welcome to Stackoverflow! Next time, please try to explain what each part of your code does, or at least explain how this answers the question. It makes it easier for those who stumble upon your code again. Thank you!

Answer 11

bookPrice = 24.95
discount = 0.60
shippingPriceRest = 0.75
shippingPriceFirst = 3.00
totalUnits = 60
bookDiscountAmount = bookPrice * discount * totalUnits
shipping = shippingPriceRest * (totalUnits - 1) + shippingPriceFirst
result = bookDiscountAmount + shipping
print('The total price for 60 books including shipping and discount `enter code here`is:')
print('Total price of the books is: ' + str(bookDiscountAmount))
print('Total Shipping is: ' + str(shipping))
print('The Total price is: ' + str(result))

Answer 12

#######################################################################################
#Your code, commented
#######################################################################################
bookPrice = 24.95
discount = .60
shippingPriceRest = .75
shippingPriceFirst = 3.00
totalUnits = 60
bookDiscountAmount = bookPrice * discount * totalUnits # Poor variable name choice. This is not the book discount amount, it's the cost of all books without shipping
shipping = shippingPriceRest * 59 + shippingPriceFirst # You should really use your variables as much as possible. Instead of 59, use totalUnits - 1
result = bookDiscountAmount + shipping
print 'The total price for 60 books including shipping and discount is: '
print 'Total price of the books is: ' + str(bookDiscountAmount)
print 'Total Shipping is: ' + str(shipping)
print 'The Total price is: ' + str(result)
#######################################################################################
#An example of your code, cleaned up
#######################################################################################
bookPrice = 24.95
discount = .60
shippingPriceRest = .75
shippingPriceFirst = 3.00
totalUnits = 60
totalCostBeforeShipping = (bookPrice * discount) * totalUnits
shipping = (shippingPriceRest * (totalUnits-1)) + shippingPriceFirst
result = totalCostBeforeShipping + shipping
print 'The total price for 60 books including shipping and discount is: '
print 'Total price of the books is: ' + str(totalCostBeforeShipping)
print 'Total Shipping is: ' + str(shipping)
print 'The Total price is: ' + str(result)
#######################################################################################
#An example of another method, using a loop
#######################################################################################
bookPrice = 24.95
discount = 40 # %
bookPriceWithDiscount = bookPrice * ((100.0-discount)/100.0)
firstBookShippingPrice = 3
otherBookShippingPrice = .75
totalBooks = 60
totalCost = 0
for book in range(totalBooks):
 if book == 0:
 totalCost += firstBookShippingPrice
 else:
 totalCost += otherBookShippingPrice
 totalCost += bookPriceWithDiscount
shipping = firstBookShippingPrice + (otherBookShippingPrice * totalBooks)
print 'The total price for 60 books including shipping and discount is:'
print 'Total price per book is: %d'%(bookPriceWithDiscount)
print 'Total shipping is: %d'%(shipping)
print 'The total price is: %d'%(result)

• Ned Batchelder: %d ? Did you try this code? A loop to incrementally add the shipping? Why??