How to compare multiple things at once

Question

let's say a='hi'

I want to know if a is any of the following 'hi', 'yes', or 'no' I could just run

a='hi'
a=='hi' or a=='yes' or a=='no'
>>>True

But let's say it is a really long list of possibilities so I just say

a='hi'
a==('hi' or 'yes')

When I do this I get the answer True But when I do something like this:

a==('yes' or 'hi')
>>>False

and then this is also weird

a==('yes' and 'hi')
>>>True

but if I switch them around again

a==('hi' and 'yes')
>>>False

Can someone explain what is happening here

Answer 1

The reason why some of your lines evaluate to True while the others evaluate to False is simply due to how and/or work in Python:

The expression x and y first evaluates x; if x is false, its value is returned; otherwise, y is evaluated and the resulting value is returned.

The expression x or y first evaluates x; if x is true, its value is returned; otherwise, y is evaluated and the resulting value is returned.

Thus, let's walk through your cases.

('hi' or 'yes')

'hi' is truthy, so this expression evaluates to 'hi'. a == 'hi' evaluates to True.

('yes' or 'hi')

Same reasoning, except now it evaluates to 'yes'. a == 'yes' is False.

('yes' and 'hi')

Since 'yes' is truthy, the expression evaluates to 'hi', and a == 'hi' is True.

('hi' and 'yes')

Finally, since this evaluates to 'yes', a == 'yes' is False.

If you want to test if a string is one of multiple things, test if it's in a set:

if a in {'hi', 'yes', 'no'}:
    # Do something