I am a beginner in Python and am working on an assignment. I keep getting TypeError: unsupported operand type(s) for -: 'int' and 'function'
even after researching the error and applying the suggested fixes. I'm not looking for anyone to hand me a solution, but I would appreciate a second look. I'm missing something but I don't know what. This is the section of code I'm having trouble with:
month = 0
interestYDT = 0
balance = int(raw_input ("Enter balance on credit card: "))
annualInterestRate = float(raw_input ("Enter annual interest rate as a decimal: "))
monthlyPaymentRate = float(raw_input ("Enter minimum monthly payment rate as a decimal: "))
previousbalance = balance
#
def monthlyInterestRate(annualInterestRate):
return float(annualInterestRate/12)
#
if month <= 12:
def minimumMonthlyPayment(previousbalance):
return (previousbalance * monthlyPaymentRate)
def monthlyInterest(monthlyInterestRate):
return (1 + monthlyInterestRate)
minMonPay = minimumMonthlyPayment
monInt = monthlyInterest
newbalance = ((previousbalance - minMonPay) * (monInt))
interestYDT = (interestYTD + montInt)
previousbalance = (newbalance)
print ''
print ('Month:' (month))
print ('Minimum monthly payment: $ ' (round(minimumMonthlyPayment, 2)))
print ('Remainging balance: $ ' (round(newbalance, 2)))
print ' '
month = (month + 1)
This is the entire error I get:
Traceback (most recent call last):
File "C:/Users/Karla/Documents/_MIT 600X Introduction to CS and Prog/Assignments/Week2/kmarciszewski_week2_Problemset_Problem1.py", line 33, in <module>
newbalance = ((previousbalance - minMonPay) * (monInt))
TypeError: unsupported operand type(s) for -: 'int' and 'function'
I'd really appreciate any insight. Thank you.
In order to call a function you must add parens after the function name, as well as any required parameters.
In these two lines
minMonPay = minimumMonthlyPayment
monInt = monthlyInterest
you assign the functions to the names minMonPay, monInt, but you don't actually call them. Rather, you would need to write something like:
minMonPay = minimumMonthlyPayment(previousBalance)
monInt = monthlyInterest(monthlyInterestRate)
This definition
def minimumMonthlyPayment(previousbalance):
return (previousbalance * monthlyPaymentRate)
gives you a function that takes one parameter and calls it previousBalance. It has nothing to do with the variable you created earlier in your code. In fact, I suggest you rename it, it can only serve to confuse you as a beginner.
Further, the functions you've created are so simple, and only used once each, that it might be in your interest to remove them and inline the code.
# OLD CODE
def minimumMonthlyPayment(previousbalance):
return (previousbalance * monthlyPaymentRate)
def monthlyInterest(monthlyInterestRate):
return (1 + monthlyInterestRate)
minMonPay = minimumMonthlyPayment
monInt = monthlyInterest
# NEW CODE
minMonPay = previousbalance * monthlyPaymentRate
monInt = 1 + monthlyInterestRate
Dont forget to update the line that incorrectly uses the minimumMonthlyPayment function if you do this.
# OLD CODE
print ('Minimum monthly payment: $ ' (round(minimumMonthlyPayment, 2)))
# NEW CODE
print ('Minimum monthly payment: $ ' (round(minMonPay, 2)))
我认为问题在于这行minMonPay = minimumMonthlyPayment
它看起来像是在为方法分配变量而不是调用方法。
Looking at your code and it looks like you are assigning a function to a variable and then trying to minus a function from a value.
You define the function 'minimumMonthlyPayment(previousbalance)', but then you assign the function to the variable 'minMonPay = minimumMonthlyPayment'. Then later you say previousBalance - minMonPay. What I think you meant to do was:
minMonPay = minimumMonthlyPayment(previousbalance)
Hope that helps.
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