What are the differences between type() and isinstance()?

Question

What are the differences between these two code fragments?

Using type():

import types

if type(a) is types.DictType:
    do_something(         


        

Answer 1

Here's an example where isinstance achieves something that type cannot:

class Vehicle:
    pass

class Truck(Vehicle):
    pass

in this case, a truck object is a Vehicle, but you'll get this:

isinstance(Vehicle(), Vehicle)  # returns True
type(Vehicle()) == Vehicle      # returns True
isinstance(Truck(), Vehicle)    # returns True
type(Truck()) == Vehicle        # returns False, and this probably won't be what you want.

In other words, isinstance is true for subclasses, too.

Also see: How to compare type of an object in Python?