Evaluation of boolean expressions in Python

Question

What truth value do objects evaluate to in Python?

Related Questions

• Boolean Value of Objects in Python: Discussion about overriding t

Answer 1

Update: Removed all duplicate infomation with Meder's post

For custom objects in Python < 3.0 __nonzero__ to change how it is evaluated. In Python 3.0 this is __bool__ (Reference by e-satis)

It is important to understand what is meant by evaluate. One meaning is when an object is explicitly casting to a bool or implicitly cast by its location (in a if or while loop).

Another is == evalutation. 1==True, 0==False, nothing else is equal via ==.

>>> None==False
False
>>> 1==True
True
>>> 0==False
True
>>> 2==False
False
>>> 2==True
False

Finally, for is, only True or False are themselves.