Is there a difference between `==` and `is` in Python?

There is a simple rule of thumb to tell you when to use == or is.

• == is for value equality. Use it when you would like to know if two objects have the same value.
• is is for reference equality. Use it when you would like to know if two references refer to the same object.

>>> a = 500
>>> b = 500
>>> a == b
True
>>> a is b
False

注： 判断None的只能用xxx is None来做

ref: http://stackoverflow.com/questions/132988/is-there-a-difference-between-and-is-in-python

https://segmentfault.com/q/1010000000150947