Inheritance Scope

When traversing an inheritance structure, the inheritance_explorer will by default walk any subclasses that are available within the scope of the python session. There are a number of ways to limit or change the scope of available subclasses.

Starting class

The most obvious way to control the extent of the graph is to select a starting class below branch points.

For example, the following maps from the QAbstractButton class of QtWidgets, showing all of the button-related QT widgets wrapped by qtpy:

from inheritance_explorer import ClassGraphTree
from qtpy.QtWidgets import QAbstractButton, QPushButton

cgt = ClassGraphTree(QAbstractButton)#, max_recursion_level=2)#, classes_to_exclude=('QAbstractButton', 'QDialog'))
cgt.show_graph()

If we instead map from QPushButton, we’ll obviously only get that branch:

cgt = ClassGraphTree(QPushButton)
cgt.show_graph()

Recursion level

We can also set the max_recursion_level argument to note how far down we want to go. In the following, we map out only the immediate children of QAbstractButton:

cgt = ClassGraphTree(QAbstractButton, max_recursion_level=0)
cgt.show_graph()

Excluding branches

By setting the classes_to_exclude argument, we can easily prune branches, leaving only those of interest:

cgt = ClassGraphTree(QAbstractButton, classes_to_exclude=('QRadioButton', 'QToolButton'))
cgt.show_graph()

Imported Packages

Finally, because the inheritance_explorer is a dynamic walker, the resulting graph can change depending on what packages you have imported! If you import packages that subclass the parent of interest, then you’ll get all those cases as well.

For example, if we map collecitons.defaultdict, we get a simple inheritance structure:

from inheritance_explorer import ClassGraphTree
from collections import defaultdict
cgt = ClassGraphTree(defaultdict)
cgt.show_graph()

But if we import a package that implements its own defaultdict child class and then re-map, we will get additional entries!

In this case, we are importing yt which uses custom defaultdict implementations in a number of places:

import yt
cgt = ClassGraphTree(defaultdict)
cgt.show_graph()