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edited May 1, 2016 at 11:13

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You don't need to define all of those functions because the operator module already did, and they happen to have the same names as yours.

You use __name__. That's great. Since you won't be defining functions anymore (because of ^^), this file will be completely useless as a module. Therefore, I probably wouldn't bother with it. I might define a function to get input and then have a while True:

def get_answer(num1, num2, op):
    ...
if __name__ == '__main__':
    while True:
        try:
            number1 = float(input(...))
            number2 = float(input(...))
        except ValueError:
            print("That is not a number!")
            continue
        operator = input(...)
        answer = get_answer(number1, number2, operator)
        if answer is None:
            print("Invalid operator!")
        else:
            print(answer)

That's just a rough draft. I probably wouldn't do that, but it is a possibility.

Never have a bare except unless you are writing your own interpreter. You should have expectations for what errors you might get. Let's say you mis-spelled number1 and said numberl. There would be an error, so it would say That is not a number! ... no matter what you type. What is your expectation? Of course, it's that the user might type an invalid float. In that case, use except ValueError:

I would use a dictionary for the different operations, and I would use the more standard operator names. That is, ^ instead of pow. I would also tell the user the options at the beginning instead of telling him each time. Here is the full program:

You don't need to define all of those functions because the operator module already did, and they happen to have the same names as yours.

def get_answer(num1, num2, op):
    ...
if __name__ == '__main__':
    while True:
        try:
            number1 = float(input(...))
            number2 = float(input(...))
        except ValueError:
            print("That is not a number!")
            continue
        operator = input(...)
        answer = get_answer(number1, number2, operator)
        if answer is None:
            print("Invalid operator!")
        else:
            print(answer)

That's just a rough draft. I probably wouldn't do that, but it is a possibility.

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created May 1, 2016 at 11:08

zondo

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import operator

operators = {
    '+': operator.add,
    '-': operator.sub,
    '*': operator.mul,
    '/': operator.truediv,
    '%': operator.mod,
    '^': operator.pow,
    '//': operator.floordiv,
    '>': operator.gt,
    '<': operator.lt,
    '=': operator.eq,
    '!=': operator.ne,
    '>=': operator.ge,
    '<=': operator.le,
}

def get_answer(num1, num2, op):
    try:
        return operators[op](num1, num2)
    except IndexError:
        raise ValueError("Invalid operator")

if __name__ == '__main__':
    operator_string = ', '.join(operators)
    print("Valid operators: {}\n".format(operator_string))
    while True:
        try:
            number1 = float(input("Enter the first number: "))
            number2 = float(input("Enter the second number: "))
        except ValueError:
            print("That is not a number!")
            continue
        except (KeyboardInterrupt, EOFError):
            break # exit
        op = input("Enter an operator: ")
        try:
            print(get_answer(number1, number2, op))
        except ValueError:
            print("Invalid operator!")