Python core Programming Notes--fourth chapter

Chapter Fourth Python objects

1. Type is also an object:

A = 4;type (a)-><type ' int ', where "<type ' int ' >" is a Type object (which can be assigned to a variable), you can use the type (type (a)) to verify

2.python2.2 start, class and type unification, class = Type, instance is object of type

3. Any object has a natural Boolean value

4. integer objects, string objects , tuple objects are immutable objects, Python efficiently caches integers and string objects , so a=3;b=1+2; (A is B) returns True, If the float type returns false. The cache range for integers is [-5,256] closed interval

Python core Programming Notes--fourth chapter