Check if any character in a string is not in another string

Question

I have a function where the user inputs the string s.
If any character in s is not in "0123456789e+-. ", the function should return False.

I tried this:

if any(s) not in "0123456789e+-. ":
    return False

This:

if any(s not in "0123456789e+-. "):
    return False

And This:

if any(character for character in s not in "0123456789e+-. "):
    return False

How should I use the any() function in this case?

`if any(character not in "0123456789e+-. " for character in s ):` — Thierry Lathuille, Jun 29 '19 at 17:05

Devesh Kumar Singh · Answer 1 · 2019-06-29T17:46:39.897

3

You want to iterate over every character in s and check if it is not in the set "0123456789e+-. "

chars = set("0123456789e+-. ")
if any(c not in chars for c in s):
    return False

You can also use all in this case to check for the same condition

chars = set("0123456789e+-. ")
if not all(c in chars for c in s):
    return False

edited Jun 29 '19 at 17:46

answered Jun 29 '19 at 17:06

How about just: `return all(c in set("0123456789e+-. ") for c in s)` ? – Austin Jun 29 '19 at 17:18
That's a good point @Austin but I didn't know if the OP wants to return `True` in the other case, hence I didn't add it – Devesh Kumar Singh Jun 29 '19 at 17:19
This will create a new set with every iteration, no? Not a big deal, but just one of those things. – Mad Physicist Jun 29 '19 at 17:41
Fair point @MadPhysicist updated accordingly! – Devesh Kumar Singh Jun 29 '19 at 17:46

score 3 · Answer 2 · edited Jun 29 '19 at 17:41

3

Just with sets difference:

pattern = "0123456789e+-. "
user_input = '=-a'

if set(user_input) - set(pattern):
    return False

or just test for negative subset:

if not set(user_input) < set(pattern):
    return False

edited Jun 29 '19 at 17:41

Mad Physicist

answered Jun 29 '19 at 17:10

RomanPerekhrest

2 Answers2