如果在元组中为string1或string2

Question

So I stumbled upon a problem (solved it eventually via experimentation) with checking for the existence of strings inside a tuple.

if 'String1' or 'String2' in tuple:

evaluated True even if neither were in tuple.

if 'String1' in tuple or 'String2' in tuple:

gives me the desired result.

What did the first variant actually evaluate?

Edit: @Cricket_007 ... the question you pointed to in your dupe report didn't cover the in , therefore I believe this not to be a dupe.

Answer 1

The difference is the in container checking, If you break this statement: if 'String1' or 'String2' in tuple:

• 'String1' returns True because testing str() returns True as long as the string is not empty

• 'String2' in tuple returns True only if the string is contained in the tuple

The first condition always returns True .

The second line tests both variables for in containment first, and then performing or between the results