Python: How to use values from divmod in a subsequent subtraction

Question

how do I include the result of a divmod division into a simple subtraction without facing: TypeError: unsupported operand type(s) for -: 'int' and 'tuple'?

Here my code (written in Python):

def discount(price, quantity): 
if (price > 100): 
    discounted_price = price*0.9
else: 
    discounted_price = price

if (quantity > 10): 
    deducted_quantity = divmod(quantity, 5)
    discounted_quantity = quantity - deducted_quantity
else: 
    discounted_quantity = quantity

#Compute which discount yields a better outcome   
if (discounted_price*quantity < price*discounted_quantity):
    return(discounted_price*quantity)
else:
    return(price*discounted_quantity)

Any help is highly appreciated since I am a beginner and I could not find a fitting solution yet.

Just for your information the underlying task: Write a function discount() that takes (positional) arguments price and quantity and implements a discount scheme for a customer order as follows. If the price is over 100 Dollars, we grant 10% relative discount. If a customers orders more than 10 items, one in every five items is for free. The function should then return the overall cost. Further, only one of the two discount types is granted, whichever is better for the customer.

`divmod` returns the quotient and remainder from the division as a tuple, as the documentation says. Do you need both values? — Carcigenicate, Mar 07 '19 at 15:15
`divmod` beasically returns `a // b, a % b`, so just choose the one you need. — Graipher, Mar 07 '19 at 15:15
Yes I need both values. How do include these values into my computations? — Jakob, Mar 07 '19 at 15:16
`quantity` is a single number; what is `17 - (3, 2)` supposed to produce? Why are you using `divmod` in the first place; what does it mean to divide `quantity` by 5 in this case? — chepner, Mar 07 '19 at 15:23
I know; however what I didnt know was how to get the individual values from the divmod. — Jakob, Mar 07 '19 at 15:24

score 1 · Accepted Answer · answered Mar 07 '19 at 15:17

divmod returns a tuple (d, m) where d is the integer result of the division (x // y) and m is the remainder (x % y), use indexing to get whatever it is you want of the two (div or mod):

deducted_quantity = divmod(quantity, 5)[0]
# or:
# deducted_quantity = divmod(quantity, 5)[1]

Or if you need both, use a variable for each value using unpacking:

the_div, the_mod = divmod(quantity, 5)

Python: How to use values from divmod in a subsequent subtraction

1 Answers1