Is "value not in list" same as "not value in list"?

Question

The two forms value not in list and not value in list return the same result.

Are they equivalent or is one better than the other?

>>> l=[1,2,3]
>>> 1 not in l
False
>>> not 1 in l
False
>>> 5 not in l
True
>>> not 5 in l
True

Answer 1

I would say value not in list is better simply because of readability. not value in list is confusing. Code should be as readable as possible.

Answer 2

From http://docs.python.org/2/reference/expressions.html#not-in:

x in s evaluates to true if x is a member of the collection s, and false otherwise. x not in s returns the negation of x in s

So, x not in s is indeed the same as not x in s. Whether one is better than the other is a matter of style; personally, I'd say that x not in s reads better.