how to use if statement to test membership of a string

Question

I'm having trouble understanding my logic in a simple Python statement. I'm trying to use 'not in' to test whether 's' or '5' is a part of the input but when I use either of them the same print statement is executed which says 's or 5 is not included'. Here is my code:

myinput = input('Enter input here')
if 's' or '5' not in myinput:
    print('s or 5 is not included')
else:
    print('s or 5 is included')

Could someone help me out? Thanks

score 0 · Answer 1 · answered Feb 20 '20 at 17:44

0

(Am certain this is a duplicate, but could not find it.)

"Neither 's' nor '5' are in myinput" is logically equivalent to "('s' is not in myinput) and ('5' is not in myinput)". (See DeMorgan's Law.)

answered Feb 20 '20 at 17:44

Scott Hunter

48,888
12
60
101

oamandawi · Accepted Answer · 2020-02-20T18:24:11.197

0

As stated by Scott Hunter

if ('s' not in myinput) and ('5' not in myinput):
    print('s or 5 is not included')
else:
    print('s or 5 is included')

De Morgan's law states that not (A or B) = not A and not B

In your example, A = 's' is in myinput, and B = '5' is in myinput

edited Feb 20 '20 at 18:24

answered Feb 20 '20 at 18:01

oamandawi

405
5
15

This code snippet works as long as I don't include the 'is' within the 'if' brackets – podjv Feb 20 '20 at 18:12
My bad, just fixed it. – oamandawi Feb 20 '20 at 18:24

how to use if statement to test membership of a string

2 Answers2