How do you round a string in Python?

Question

I am new to Python and a student, my college has chosen the worst book on earth for our course. I cannot find examples of any concepts, so I apologize in advance as I know these concepts are very basic. I hope you can help me.

I need to know how to use the round feature in a string. I find examples but they do not show the string, just simple numbers.

Here is what we are supposed to get as an output: Enter the gross income: 12345.67 Enter the number of dependents: 1

The income tax is $-130.87 <---- this is what we are supposed to figure out

Here is the coding we are given to alter:

TAX_RATE = 0.20
STANDARD_DEDUCTION = 10000.0
DEPENDENT_DEDUCTION = 3000.0

# Request the inputs
grossIncome = float(input("Enter the gross income: "))
numDependents = int(input("Enter the number of dependents: "))   

# Compute the income tax
taxableIncome = grossIncome - STANDARD_DEDUCTION - \
                DEPENDENT_DEDUCTION * numDependents
incomeTax = taxableIncome * TAX_RATE 

# Display the income tax

print("The income tax is $" + str(incomeTax))

As I do not have an NUMBER to plug into the formula - I have to figure out how to use "incomeTax" - I have no idea how to do this. THe book doesnt explain it. Help?

Answer 1

You can use format strings:

print("The income tax is ${:.2f}".format(incomeTax))

If you are using Python 3.6+, you can also use f-strings:

print(f"The income tax is ${incomeTax:.2f}")

Answer 2

You can round just before making it a string:

print("The income tax is $" + str(round(incomeTax,2)))

Output:

Enter the gross income: 12345.67
Enter the number of dependents: 1
The income tax is $-130.87