Python: Program not checking full or statement

Question

some assistance is needed:

I've been having some trouble with the OR operand ...I understand how it works ( either or condition must be true), but i'm not sure why it is behaving in the fashion explained below.

The 'or' statement doesn't seem to be checking the second condition in my "flowContol' function.. when I enter 'y' it sees the condition as true and runs without any problems... however when i enter 'yes' it evaluates the condition as false...

-I excluded the other functions-..

def flowControl():
    answer = input("do you want run the 'displayLession' function? ( yes or 
    no)").strip()
    if answer == ('y' or 'yes'):
        displayLesson()
else:
    userTime()
    print('End program')

flowControl()

'y' or 'yes' always returns 'y'. `or` always returns the first value that is True, so you are comparing always with 'yes' — joaquin, Jan 07 '18 at 10:28

score 0 · Answer 1 · answered Jan 07 '18 at 10:29

0

What you are looking for is

if answer == 'y' or answer == 'yes':

Or

if answer in ['y', 'yes']:

Why? Simple, your code evaluates before what is between parentheses 'y' or 'yes' and this is 'y', because 'y' is a truthy expression in python, so no need to evaluate the latter expression.

answered Jan 07 '18 at 10:29

Ursus

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hmm...never heard of that term "Truthy expression"..sorry for the confusion.. but is it choosing 'y' simply because it's 'y'??? – Jeff - Mci Jan 07 '18 at 10:40
An expression considered True – Ursus Jan 07 '18 at 10:40
Something whose value is not directly True (maybe) but it evaluates to True in a boolean context, and this is a boolean context – Ursus Jan 07 '18 at 10:42
ah i see thanks for clarifying – Jeff - Mci Jan 07 '18 at 10:53
My pleasure Sir – Ursus Jan 07 '18 at 10:54

Python: Program not checking full or statement

1 Answers1