Getting an object by name

Question

Is it possible to create an instance of a class by giving its name, e.g.:

instance = "TestXYZ"()

Assuming that TestXYZ is imported by a class that imports the code above and TestXYZ is defined as:

class TestXYZ(object): ...

It is possible using globals()["TestXYZ"](), but why do you want to do this? — Ashwini Chaudhary
– Ashwini Chaudhary, Commented Feb 6, 2014 at 15:55
Because I don't like to pass the exact class object, but I know the name. — Michel Keijzers
– Michel Keijzers, Commented Feb 6, 2014 at 16:00
Is there a reason why you don't want to pass the class itself? — lanzz
– lanzz, Commented Feb 6, 2014 at 16:53

NPE · Accepted Answer · 2014-02-06 15:55:30Z

Yes, it is possible. The mechanics depend on how you import the class:

>>> globals()["TestXYZ"]() <__main__.TestXYZ object at 0x10f491090>

or

>>> getattr(sys.modules["test_module"], "TestXYZ")() <test_module.TestXYZ object at 0x10cf22090>

warvariuc · Accepted Answer · 2014-02-06 15:56:22Z

You can get a reference to an object from current namespace using:

klass = globals()['TestXYZ']

Then you can create an instance of the class:

instance = klass()

Ashwini Chaudhary · Accepted Answer · 2014-02-06 15:59:52Z

I am not sure why do you want to do this, but instead of using globals() I'd suggest you to create a dictionary here:

class Foo: pass d = {'Foo':Foo} ins = d['Foo']()

Or move the class to some other module:

import some_module ins = getattr(some_module, 'Foo')()

3 Answers 3