Question 1

How to speed up Pylance in a large Python project?

Accepted Answer

Set python.analysis.diagnosticMode to 'openFilesOnly', exclude unnecessary directories with python.analysis.exclude, and use the 'light' languageServerMode to reduce indexing and type checking overhead, as recommended in the performance settings.

Question 2

Pylance vs Pyright: which one should I use?

Accepted Answer

Pylance is the default language server for VS Code, built on Pyright but adding features like semantic highlighting and AI integration. Use Pyright if you need a standalone type checker or work outside VS Code, but for VS Code users, Pylance provides a more integrated experience.

Question 3

How do I enable strict type checking in Pylance?

Accepted Answer

Set python.analysis.typeCheckingMode to 'strict' in your settings.json, but note that this can be overridden by pyrightconfig.json or pyproject.toml files in your project, and it may impact performance due to increased analysis.

Question 4

Can I use Pylance with Jupyter Notebooks?

Accepted Answer

Yes, Pylance supports Jupyter Notebooks within VS Code, offering code completion, navigation, and diagnostics directly in notebook cells, as mentioned in the features list for compatibility.

Question 5

Why is Pylance so slow on my machine?

Accepted Answer

Check your python.analysis settings: disable indexing or reduce userFileIndexingLimit, set typeCheckingMode to 'off' or 'basic', and ensure exclude paths are configured to avoid analyzing unnecessary files, as these adjustments can improve performance.

Question 6

Is Pylance free to use?

Accepted Answer

Yes, Pylance is free and included with the Python extension for VS Code, but some AI-assisted features require GitHub Copilot, which may have separate licensing or costs.

Question 7

How to fix missing import errors in Pylance?

Accepted Answer

Use the quick fix actions to add imports, configure python.analysis.extraPaths for custom modules, or enable python.analysis.enableTroubleshootMissingImports with the Python Environments extension, as described in the code actions section.

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