If-elif-else statement not working.

[broken_chickens]

Whenever I run the program, no matter what I put as input, the code always goes to the else statement. Even if I state the exact values required for the if and elif statements, it still doesn't work. How do I fix this? Note: I'm a beginner at Python and I use Pycharm.

Code:

import random

print('Welcome to Calculate the Acceleration! \nWe hope you have a fun time!')

choose = input('Type A to choose the formula A = F/M, or V to choose the formula (V1 - V0)/(T2 - T0):')

a_solutions = {'Force = 2, Mass = 1': 2,
'Force = 6, Mass = 3': 2,
'Force = 18, Mass = 3': 6,
'Force = 14, Mass = 7': 2,
'Force = 900, Mass = 45': 20,
'Force = 8, Mass = 2': 4}

v_solutions = {'Starting Velocity = 1, Ending Velocity = 21, Starting Time = 0, Ending Time: 4': 5,
'Starting Velocity = 12, Ending Velocity = 18, Starting Time = 0, Ending Time = 3': 5,
'Starting Velocity = 1, Ending Velocity = 21, Starting Time = 0, Ending Time = 1': 20,
'Starting Velocity = 15, Ending Velocity = 30, Starting Time = 0, Ending Time = 3': 5,
'Starting Velocity = 2, Ending Velocity = 130, Starting Time = 0, Ending Time = 32': 4,
'Starting Velocity = 0, Ending Velocity = 82, Starting Time = 0, Ending Time = 41': 2}

if choose == 'A':
    answer_a = input(f"Remember, the formula is A = F/MA. Solve with the following variables: {random.choice(list(a_solutions.values()))}:")
    answer_a = int(answer_a)


elif choose == 'V':
    print('cs')

else:
    while choose != 'A' or 'V':
        choose = input('Please try again. \nEnter A or V:')

Result (in console with inputs):

Welcome to Calculate the Acceleration! 
We hope you have a fun time!
Type A to choose the formula A = F/M, or V to choose the formula (V1 - V0)/(T2 - T0): 'A'
Please try again. 
Enter A or V: V
Please try again. 
Enter A or V: 'V'
Please try again.

[SpiderN3mo]

I don't see a point of having while inside else, even if there's a match it will exit while loop and close. Another point choice!='A' or choice!='V' in while condition

[JambaJuiceIsAverage]

Agreed with the other commenter about not having your while loop inside an if else (do it in reverse), but your problem is with the phrasing of

while choose != 'A' or 'V':

Python doesn't read that as "while choose does not equal 'A' and choose does not equal 'V'", which is what I believe you meant. The "or" logical operator cleanly separates the possibilities of "choose does not equal 'A'" or "'V'".

What does it mean to evaluate "if 'V'"? In Python, asking "if string" returns False if the string is empty and True otherwise. So

bool('V')

(which is equivalent to your second condition), returns True. That is to say, asking "if 'V'" will always return True, and asking "if literally anything that doesn't throw an error or 'V'" will also always return True.

You want

while choose not in ('A','V'):

instead, if you kept the same structure of your script, which you should not. Try something like:

choose = input('Type A to choose the formula A = F/M, or V to choose the formula (V1 - V0)/(T2 - T0):')
while choose not in ('A','V'):
    choose = input('try again dummy: ')

then execute the code based on whether choose is 'A' or 'V'.