Python input addition

[Anglogang]

Hello, I just started Python programming and I have started experimenting with all the math operators, and I am trying to make the program add three user inputs, two of which are changed through operations into a new variable, and I want to add the two new variables with the last one. The error I am getting is the following:

Traceback (most recent call last):
  File "D:\PythonCode\function.py", line 6, in <module>
    print(a1+b1+c)
TypeError: unsupported operand type(s) for +: 'NoneType' and 'NoneType'

Here is the code

a = int(input("Input your a variable ") )
a1 = print(int(a ** (2))) 
b = int(input("Input your b variable ") )
b1 = print(int(b * a))
c = int(input("Input your constant ") )
print(a1+b1+c)

I apologize for the horrendous explanation, but it was the best I could do.

Thanks

[79wjd]

a1 and b1 aren't ints. 

 

Instead do something like this: 

a=input("input your a variable")

a1 = a1*2

print a1

 

b=input("input your b variable")

b1=b*a

print b1

 

c=input("input your constant")

print a1+b1+c

 

[Anglogang]

1 minute ago, djdwosk97 said:

change it to:

 

print(a+b+c)

 

My plan was to add the new variables a1 and b1 to c

[79wjd]

1 minute ago, Anglogang said:

My plan was to add the new variables a1 and b1 to c

see my edit

[Anglogang]

3 minutes ago, djdwosk97 said:

see my edit

Thank you, it worked! Although I needed to specify that the input was an integer.

Thanks again

[straight_stewie]

1 hour ago, Anglogang said:

Hello, I just started Python programming and I have started experimenting with all the math operators, and I am trying to make the program add three user inputs, two of which are changed through operations into a new variable, and I want to add the two new variables with the last one. The error I am getting is the following:

// The following will not do any type checking. If the user enters a character then it will break

user_one = int(input("Please enter an integer: "))
user_one = user_one ** 2
print(user_one)
  
user_two = int(input("Please enter another integer: "))
user_two *= user_one
print(user_two)
  
user_three = int(input("Please enter a third integer: "))
user_three += user_two + user_one
print(user_three)
  
  
// The following will do simple type checking. If the user does not enter an integer, then the program will respond appropriately.
  
def get_input():
	
	while True:
		try:
			user_value = int(input("Please enter an integer: "))
			return user_value
              
		except:
			print("You did not enter an integer. Please only enter an integer")
              

def main():
	user_a = get_input() ** 2
	print(user_a)
      
	user_b = get_input() * user_a
	print(user_b)
      
	user_c = get_input() + user_b + user_a
	print(user_c)

main()

 

[vorticalbox]

15 minutes ago, straight_stewie said:

// The following will not do any type checking. If the user enters a character then it will break

user_one = int(input("Please enter an integer: "))
user_one = user_one ** 2
print(user_one)
  
user_two = int(input("Please enter another integer: "))
user_two *= user_one
print(user_two)
  
user_three = int(input("Please enter a third integer: "))
user_three += user_two + user_one
print(user_three)
  
  
// The following will do simple type checking. If the user does not enter an integer, then the program will respond appropriately.
  
def get_input():
	
	while True:
		try:
			user_value = int(input("Please enter an integer: "))
			return user_value
              
		except:
			print("You did not enter an integer. Please only enter an integer")
              

def main():
	user_a = get_input() ** 2
	print(user_a)
      
	user_b = get_input() * user_a
	print(user_b)
      
	user_c = get_input() + user_b + user_a
	print(user_c)

main()

 

agreed it is always better to update the first variable rather than set a new one, uses up more memory otherwise. 

[Anglogang]

1 hour ago, vorticalbox said:

agreed it is always better to update the first variable rather than set a new one, uses up more memory otherwise. 

On a side note, how would I get the input to accept multiple variable types? For example, allowing the input to except integers, fractions, and floating point numbers

[fizzlesticks]

6 minutes ago, Anglogang said:

On a side note, how would I get the input to accept multiple variable types? For example, allowing the input to except integers, fractions, and floating point numbers

You can use the Fraction type and either leave it as a fraction or check the denominator for a 1 to convert to int or convert to float for anything else.

[Claryn]

You are initializing a1 and b1 to the print-function. You can't necessarily do that, and specially not try to add them together with an int.

[straight_stewie]

2 hours ago, Anglogang said:

On a side note, how would I get the input to accept multiple variable types? For example, allowing the input to except integers, fractions, and floating point numbers

The best way to make a calculator (which I believe is what you're really after) is to use Dijsktra's Shunting Yard Algorithm to parse infix expressions into post fix expressions and then execute the post fix expressions.

 

Accepting all of the possible types isn't really hard, it's just time consuming. There's multiple ways to do it, but the easiest to understand and implement would be to build nested try/except structures like I showed you in my previous example.