Python: Having trouble to terminate "while" loop under two consecutive condition

Question

I don't know what is the problem, but I can't end a while loop if it is under two if conditions. Let me show the code:

while True:
    k = input ("Please enter 'hello': ")
    if k == "hello":
        m = input ("Are your Sure? (Y/N): ")
        if m == "Y" or "y" or "yes" or "Yes":
            break

Now, after the second prompt, even if i type no or any other things, while loop still ends. I only want to end it after second confirmation. What is my mistake in the coding?

pls, properly indent your code. – Avinash Raj Dec 23 '15 at 06:48 — Avinash Raj, Dec 23 '15 at 06:48

The6thSense · Answer 1 · 2015-12-23T06:58:36.033

5

This is what internally happens.

Your code:

m == "Y" or "y" or "yes" or "Yes"

Python Interpretation:

(m == "Y" )or ("y" or "yes") or "Yes"

("y" or "yes") will always produce y since it is not a falsey value then ("y" or "yes") or "Yes" is changed to this "y" or "Yes" again same value so finally (m == "Y" )or ("y" or "yes") or "Yes" is changed to (m == "Y" )or "y"

To avoid this you could use separate checking for all the condition or in as BenC stated

Or Even more simply

m.lower() in "yes" # Note that it also True if m is e or es or s etc..

      or

"yes".startwith(m.lower()) # This work perfectly as per my test cases

edited Dec 23 '15 at 06:58

answered Dec 23 '15 at 06:52

The6thSense

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upvoted for `"yes".startwith(m.lower())` cool :) – Vivek Sable Dec 23 '15 at 07:08
@VivekSable thanks just thought of a different way to do it :P. – The6thSense Dec 23 '15 at 07:40

score 1 · Answer 2 · answered Dec 23 '15 at 06:51

1

It should look like this:

if m == "Y" or m == "y" or m == "yes" or m == "Yes":

answered Dec 23 '15 at 06:51

scope

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Vivek Sable · Answer 3 · 2015-12-23T06:59:29.583

change or condition

Demo:

>>> while True:
...     k = raw_input ("Please enter 'hello': ")
...     if k == "hello":
...         m = raw_input ("Are your Sure? (Y/N): ")
...         if m == "Y" or m == "y" or m == "yes" or m == "Yes":
...             break
... 
Please enter 'hello': hello
Are your Sure? (Y/N): y
>>>

we can use lower string method to convert string to lower case,

Demo:

>>> m = raw_input ("Are your Sure? (Y/N): ").lower()
Are your Sure? (Y/N): Yes
>>> m
'yes'

Note:

Use raw_input() for Python 2.x

USe input() for Python 3.x

Python: Having trouble to terminate "while" loop under two consecutive condition

3 Answers3