Visualizing Python's Data Model: References, Mutability, and Copying Made Clear

[u/Sea-Ad7805]

Many Python beginners (and even experienced devs) struggle with concepts like:

• references vs. values

• mutable vs. immutable data types

• shallow vs. deep copies

• variables pointing to the same object across function calls

• recursion and the call stack

To write bug-free code, it's essential to develop the right mental model of how Python actually handles its data. Visualization can help a lot with that. I've created a tool called memory_graph, a teaching tool and debugger aid that generates visual graphs of Python data structures including: shared references, nested structures, and the full call stack.

It helps answer questions like:

• “Does this variable share any values with that one?”

• “What part of this object is actually copied?”

• “What does the call stack look like in this recursive call?”

You can generate a memory graph with a single line of code:

import memory_graph as mg
a = [4, 3, 2]
b = a
b.append(1)
mg.show(mg.stack())  # show graph of the call stack

It also integrates in IDEs like VS Code, Cursor AI, and PyCharm for real-time visualization while stepping through code in the debugger.

Would love feedback from Python educators, learners, and tooling enthusiasts.

• memory_graph on GitHub

• memory_graph subreddit