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Python

Posted by Jason Ladieu
Jason Ladieu
10,635 Points

Checking multiple conditions in one conditional statement question.

Hi there,

I'd like to test two conditions using one conditional statement (if possible) in the first_num and second_num functions. I can't figure out how to make the condition I have fail if a string is entered. I'd also like the condition to pass if float is entered. For this I think I would need two conditional statements, but if it can be in one it would be better! Any help is much appreciated !

# My Calculator Script: version 1.0



# Collect first number and check for integer or float
def first():
    global first_num
    first_num = int(input("Please enter the first number:\n"))
    if first_num == 0:
        print("Error, please choose a value other than 0.\n")
        first()


# Collect and check for operator         
def operators():
    global enter_op
    enter_op = input("Please enter an operator. You can choose: -, +, /, or *.\n")
    enter_op = str(enter_op)
    if enter_op not in ("-", "+", "/", "*"):
        print("Error, please enter a valid operator. You can choose from -, +, /, or *.\n")
        operators()

# Collect second number and check for integer or float

def second():
    global second_num
    second_num = int(input("Please enter the second number:\n"))
    if second_num == 0:
        print("Error, please choose a value other than 0.\n")
        second()
    second_num = int(second_num)





#solve and print 
def solution():
    if enter_op == ('+'):
        print('{} + {} = '.format(first_num, second_num))
        print(first_num + second_num)
    elif enter_op == ('-'):
        print('{} - {} = '.format(first_num, second_num))
        print(first_num - second_num)
    elif enter_op == ('/'):
        print('{} / {} = '.format(first_num, second_num))
        print(first_num / second_num)
    elif enter_op == ('*'):
        print('{} * {} = '.format(first_num, second_num))
        print(first_num * second_num)
    else:
        print("What happened!")


#execute function

def solve():
    first()
    operators()
    second()
    solution()

solve()

1 Answer

Nathan Tallack
Nathan Tallack
22,164 Points
Nathan Tallack
Nathan Tallack
22,164 Points

The beauty of Python is that it reads well.

Consider:

if True or True:
    print("This is true!")

if True or False:
    print("This is also true!")

if True and False:
    print("This is false!")

if (True and False) or (True and True):
    print("This is true!")

Python is awesome! :)

Jason Ladieu
Jason Ladieu
10,635 Points

Thanks for the answer! How can I make the condition fail if a string was entered ?

Nathan Tallack
Nathan Tallack
22,164 Points
Nathan Tallack
Nathan Tallack
22,164 Points

If you want have the condition test if it is of type string then you can do this.

if isinstance(1, int):
    print("This is an integer!")
if isinstance("foo", str):
    print("This is a string!")

...etc.

So what you are using here is an inbuilt python function called isinstance which takes the object or literal that you want to test as the first parameter and the type as the second parameter returning True or False accordingly.