1.16 The types Module

The types module contains type objects for all object types defined by the standard interpreter, as Example 1-86 demonstrates. All objects of the same type share a single type object. You can use is to test if an object has a given type.

Example 1-86. Using the types Module

File: types-example-1.py

import types

def check(object):
    print object,

    if type(object) is types.IntType:
        print "INTEGER",
    if type(object) is types.FloatType:
        print "FLOAT",
    if type(object) is types.StringType:
        print "STRING",
    if type(object) is types.ClassType:
        print "CLASS",
    if type(object) is types.InstanceType:
        print "INSTANCE",
    print

check(0)
check(0.0)
check("0")

class A:
    pass

class B:
    pass

check(A)
check(B)

a = A()
b = B()

check(a)
check(b)

0 INTEGER
0.0 FLOAT
0 STRING
A CLASS
B CLASS
<A instance at 796960> INSTANCE
<B instance at 796990> INSTANCE

Note that all classes have the same type, as do all instances. To test what class hierarchy a class or an instance belongs to, use the built-in issubclass and isinstance functions.

The types module destroys the current exception state when it is first imported. In other words, don't import it (or any module that imports it!) from within an exception handler.