There are two built-in functions that help you identify the type of an object. You can use type()
if you need the exact type of an object, and isinstance()
to check an object’s type against something. Usually, you want to use isinstance()
most of the times since it is very robust and also supports type inheritance.
To get the actual type of an object, you use the built-in type()
function. Passing an object as the only parameter will return the type object of that object:
>>> type([]) is list True >>> type({}) is dict True >>> type('') is str True >>> type(0) is int True
This of course also works for custom types:
>>> class Test1 (object): pass >>> class Test2 (Test1): pass >>> a = Test1() >>> b = Test2() >>> type(a) is Test1 True >>> type(b) is Test2 True
Note that type()
will only return the immediate type of the object, but won’t be able to tell you about type inheritance.
>>> type(b) is Test1 False
To cover that, you should use the isinstance
function. This of course also works for built-in types:
>>> isinstance(b, Test1) True >>> isinstance(b, Test2) True >>> isinstance(a, Test1) True >>> isinstance(a, Test2) False >>> isinstance([], list) True >>> isinstance({}, dict) True
isinstance()
is usually the preferred way to ensure the type of an object because it will also accept derived types. So unless you actually need the type object (for whatever reason), using isinstance()
is preferred over type()
.
The second parameter of isinstance()
also accepts a tuple of types, so it’s possible to check for multiple types at once. isinstance
will then return true, if the object is of any of those types:
>>> isinstance([], (tuple, list, set)) True