Import a class with a string

Question

Given dot-notation of a python class, how would I import it if it's given as a string?

For example:

>>> from ingest.models import ItemInstance
>>> ItemInstance
<class 'ingest.models.ItemInstance'>

Given the string, 'ingest.models.ItemInstance', how would I import that?

Note: the above referenced duplicated is primarily about importing a module. Here I'm looking to specifically import a class. For example:

s = "ingest.models.ItemInstance"
cls = s.split('.')[-1] # works with the given path, but not always
module = '.'.join(s.split('.')[:-1])
getattr(importlib.import_module(module), cls)

The answer provided below addresses this accurately.

Mert Köklü · Accepted Answer · 2019-10-31T21:57:35.377

2

In Python 2.7 and Python 3.1 or later, you can use importlib:

import importlib

i = importlib.import_module("module_name")

If you want to access the class, you can use getattr:

import importlib
module = importlib.import_module("module_name")
class_ = getattr(module, class_name)
instance = class_()

edited Oct 31 '19 at 21:57

answered Oct 31 '19 at 21:39

Mert Köklü

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Note, this will import the *module* (here 'ingest.models') but not the whole string including the class ItemInstance. – Daniel Roseman Oct 31 '19 at 21:40
@DanielRoseman is there a way to get the actual class? The answer in the duplicate question also seem to talk primarily about importing modules/files. – user12282936 Oct 31 '19 at 21:54
Is my edited answer what you want? – Mert Köklü Oct 31 '19 at 21:57
@Marceline perfect, yes, exactly what I was looking for (not what the duplicate of just importing the module does). Thank you! – user12282936 Oct 31 '19 at 21:59

Import a class with a string

1 Answers1