This will probably be a dumb question, but why does this piece of code behave like this?

>>> test = ['aaa','bbb','ccc']
>>> if 'ddd' or 'eee' in test:
...     print True
... 
True
>>> 

I was expecting nothing printed on the stdio, because none of the strings in the IF statement are in the list.

Am I missing something?

if 'ddd' or 'eee' in test

is evaluated as:

if ('ddd') or ('eee' in test):

as a non-empty string is always True, so or operations short-circuits and returns True.

>>> bool('ddd')
True

To solve this you can use either:

if 'ddd' in test or 'eee' in test:

or any:

if any(x in test for x in ('ddd', 'eee')):