Why Does `__import__` Fail to Fully Import Matplotlib Submodules, and How Can I Fix It?

Importing Modules from String Variables with "__import__"

When attempting to document specific submodules within the matplotlib (MPL) library, it may be necessary to import these submodules from strings. However, using the "__import__" function can produce unexpected results compared to standard import statements.

Problem:

Importing a submodule using "__import__" (e.g., __import__('matplotlib.text')) does not fully load the submodule's contents as expected. Upon comparing the list of attributes obtained from both "__import__" and a regular import, it is evident that "__import__" includes base definitions from matplotlib along with extraneous elements but lacks crucial classes from the target submodule.

Solution:

To load a submodule from a string using "__import__", specify an empty list as the second argument (fromlist):

import matplotlib.text as text
x = dir(text)

i = __import__('matplotlib.text', fromlist='')
y = dir(i)

This revised code effectively loads the desired submodule, yielding the expected list of attributes.

Alternatively, in Python versions 3.1 or later, one can utilize the importlib module:

import importlib

i = importlib.import_module("matplotlib.text")
y = dir(i)

Notes:

• For imports involving sub-folders (e.g., ./feature/email.py), use importlib.import_module("feature.email").
• In Python versions prior to 3.3, an __init__.py file was required within the folder of the imported file. However, after 3.3, this requirement was removed.

The above is the detailed content of Why Does `__import__` Fail to Fully Import Matplotlib Submodules, and How Can I Fix It?. For more information, please follow other related articles on the PHP Chinese website!