i am getting Error while checking string value in list

Question

i am checking two values inside list using if condition and another string should not be in list in python below is my code but it is giving wrong output

lis = ['a','b','c','d','e','f'] #list values or lis =[]
if ('z' or 'a') and not 'x' in lis :
    print "yes"
else :
    print "no"

and output is

yes

is there anything wrong?

Is this a question or an opinion? Either way, your `if` doesn't do what you think it does. — pstatix, Apr 02 '18 at 17:01
question how to achieve this requirement i now in java but in python!!! — giveJob, Apr 02 '18 at 17:02
Output of above code will be `yes` as the `if` condition is `True`. [Among 'z' or 'a', the list has 'a'. and the list does not have any 'x'.] — Atur, Apr 02 '18 at 17:02
@DanielRoseman : There is an 'and' clause between the two conditions. I agree that first condition is always `True` and second condition is based on the elements of `lis`. Combining both conditions (with give data in second condition) will yield the result as 'yes' . — Atur, Apr 02 '18 at 17:19
lis = ['a', 'b', 'c', 'd', 'e', 'f'] if ('z' in lis or 'a' in lis) and not 'y' in lis : print('yes') else: print('no') it will meet your requirment enjoyyyyyyyyy — , Apr 02 '18 at 17:25

Keyur Potdar · Answer 1 · 2018-04-02T17:55:47.053

1

In your code, the if statement evaluates like this:

('z' or 'a') -> 'z' (which is truthy)
not 'x' in lis - > True

So, it becomes if 'z' and True, which is True.

Use this code instead:

lis = ['a', 'b', 'c', 'd', 'e', 'f'] 
if any(item in lis for item in ('z', 'a')) and 'x' not in lis:
    print 'yes'
else:
    print 'no'

This will check if any of the items in the tuple ('z', 'a') are in the list, and whether 'x' isn't.

edited Apr 02 '18 at 17:55

answered Apr 02 '18 at 17:03

Keyur Potdar

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if lis = [ ] still output is "yes" any way @keyuor diamond – giveJob Apr 02 '18 at 17:50

score 1 · Accepted Answer · answered Apr 02 '18 at 17:05

1

('z' or 'a') evaluates to be a truthy value ('z') and hence you get yes as output.

lis = ['a','b','c','d','e','f'] #list values or lis =[]
if 'z' in lis or 'a' in lis and not 'x' in lis :
    print "yes"
else :
    print "no"

answered Apr 02 '18 at 17:05

bhansa

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if ('z' in lis or 'a' in lis) and not 'x' in lis : this output giving is correct – giveJob Apr 02 '18 at 17:18
what is truthy value??? – Apr 02 '18 at 17:29
@ParaM, have a look at https://stackoverflow.com/questions/39983695/what-is-truthy-and-falsy-in-python-how-is-it-different-from-true-and-false – Keyur Potdar Apr 02 '18 at 17:33
@ParaM, thx for your brackets help – giveJob Apr 02 '18 at 17:44

score -1 · Answer 3 · edited Apr 02 '18 at 20:00

-1

In the first condition, you're making a generic statement that is considered true. If you want to see if z or a is in lis, it should look like this:

lis = ['a','b','c','d','e','f'] #list values
if ('z' or 'a') in lis and not 'x' in lis :
    print "yes"
 else :
     print "no"

edited Apr 02 '18 at 20:00

ndmeiri

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answered Apr 02 '18 at 17:02

bruckerrlb

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if ('z' or 'a') in lis and not 'x' in lis : output is "no" it wrong output please check in – giveJob Apr 02 '18 at 17:06
The question was edited after I answered. You originally had if ('z' or 'z') which made me think you were looking for "no" but were getting "yes", that's what I was answering for... – bruckerrlb Apr 02 '18 at 17:33
@para m answer is correct out put even list is empty – giveJob Apr 02 '18 at 17:38

i am getting Error while checking string value in list

3 Answers3