Trouble with the 'or' operator with strings in Python 3.2

Question

I'm having some serious issues with getting the 'or' operator to work with strings in python 3.2

My code is similar to this:

   def choose_colour():

    cmd = input("Enter command here: ")

    if cmd != ("green") or ("blue") or ("yellow"):

        choose_colour()

    if cmd == ("green"):

        colour = ("g")

    if cmd == ("blue"):

        colour = ("b")

    if cmd == ("yellow"):

        colour = ("y")

    print (colour)

choose_colour()

However if I enter either one of these colours or not, it still repeats the 'choose_colour' function.

What am I doing wrong?

are you indenting properly, sorry for asking it's just that from the code above I cannot be sure. — Jay T., Feb 22 '16 at 19:27
yeah, it's all indented correctly (im not too sure how to indent on this website) — , Feb 22 '16 at 19:37

ᴀʀᴍᴀɴ · Answer 1 · 2016-02-22T19:56:04.970

1

If you try to use != for three condition you should apply != to all of them :

if cmd != ("green") or cmd != ("blue") or cmd != ("yellow"):

In Python we cant use != operator as you used in question . For example see here :

a = 1
b = 2
c = 1
if a == c or b:
    print ("ok")  # it will print ok how ever conditions a==b==c not satisfied

Because the conditions here checking is a == c and b==True not a==c and a==b.

edited Feb 22 '16 at 19:56

answered Feb 22 '16 at 19:21

ᴀʀᴍᴀɴ

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That doesn't seem to make a difference, still does the same as before. – Feb 22 '16 at 19:32
@solluu add a sample input output into your question , so we can help you better – ᴀʀᴍᴀɴ Feb 22 '16 at 19:33
ive edited the question now – Feb 22 '16 at 19:40
Please edit your indentation , I dont understand where fucntion ends – ᴀʀᴍᴀɴ Feb 22 '16 at 19:41
sorry about that, took me a while how to indent on this website – Feb 22 '16 at 19:45
@Arman, The first two examples are equivalent. If cmd = 'green', or example, the first compound condition will evaluate to true since it is True that cmd != 'blue' while it will evaluate to False in the second. – Garrett R Feb 22 '16 at 19:50
@GarrettR I didn't get what you mean – ᴀʀᴍᴀɴ Feb 22 '16 at 19:52
Try assigning 'green' to cmd. And then evaluate the two conditions that you present: if cmd != ("green") or cmd != ("blue") or cmd != ("yellow"): and if cmd not in ["green","blue","yellow"]: They return different answers. – Garrett R Feb 22 '16 at 19:53
@GarrettR Yeah , thats true my fault – ᴀʀᴍᴀɴ Feb 22 '16 at 19:55

Trouble with the 'or' operator with strings in Python 3.2

1 Answers1