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
Is there a difference between `==` and `is` in Python?
原文：http://www.cnblogs.com/pinganzi/p/6225423.html