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Questions tagged [pylance]

Pylance is an extension for Visual Studio Code that provides a language server for Python. When applying this tag to your question, consider also tagging it with [visual-studio-code] and/or [python].

Pylance is a language server to support the core Python extension for Visual Studio Code. Its aim is to help developers write Python code better and faster by providing auto-imports, semantic highlighting, built-in reporting of warnings and errors, strict type-checking, and method signatures with type information when displaying the popup Intellisense documentation.

It was first introduced in a post on Microsoft's Python development blog: Announcing Pylance: Fast, feature-rich language support for Python in Visual Studio Code:

To deliver an improved user experience, we’ve created Pylance as a brand-new language server based on Microsoft’s Pyright static type checking tool. Pylance leverages type stubs (.pyi files) and lazy type inferencing to provide a highly-performant development experience. Pylance supercharges your Python IntelliSense experience with rich type information, helping you write better code, faster. The Pylance extension is also shipped with a collection of type stubs for popular modules to provide fast and accurate auto-completions and type checking.

It was made available starting VS Code 1.49 (2020.8.0 (12 August 2020) release).

  1. Expose Pylance setting in python.languageServer. If Pylance extension is not installed, prompt user to install it. (#13122)

Installation is straightforward:

  1. Install the Pylance extension
  2. Configure your settings.json file 
    "python.languageServer": "Pylance",
  3. Open a .py file and the extension should activate

For more information:

465 questions
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Pylance issues from google-cloud-sdk

Pylance displays errors for Google Cloud SDK after I reinstalled Windows. from google.appengine.ext import ndb class Example(ndb.Model): basic_example = ndb.StringProperty() The first issue, up by the import: Import "google.appengine.ext"…
Niklas Ternvall
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Generate .pyi file which includes docstrings for .pyd binaries

I recently compiled opencv from source and am currently trying to get autocompletion and tooltips to work on vscode while using pylance language server. Unfortunately pylance does not support .pyd binary files. As a temporary solution i figured i…
winsid
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Can the * (unpacking) operator be typed in Python? Or any other variadic args function such that all variadic types are in the result type?

Working with type stubs, I'm wondering if it's possible to express a type in Python that allows you to type this correctly for any number of arguments: def test(*args): return args At first glance, I came with: T = TypeVar('T') def test(*args: T)…
ssice
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Why is pylance unable to resolve the local relative path import (VSCode)?

Environment: Python 3.6.9 VSCode Pylance The structure of my workspace in VSCode is: .../sync ├── README.rm ├── script-program-1 │ ├── lib │ │ ├── __init__.py │ │ └── queries.py │ └── sync.py ├── lib │ ├── __init__.py │ ├──…
Matt Henry
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When I 'Run Selected' in Python on Visual Studio Code, it is suddenly opening up two Python terminals, one of which does not run my Python code

I was developing some Python code for work, using Python extension v2023.10.0 on VS Code. It was working completely fine before. Then all of a sudden when I ran some of my selected code as usual with Shift+Enter on my Python code, it opened up two…
kodikai
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How to avoid Pylance errors for functions with multiple signature for output?

I am trying to modify my project to be Pylance compliant and I am having the following issue: Lets say that I have a function of the form: def foo(a: int) -> int | list[int]: if a > 0: return a else: return [a] Then in the…
CoilM
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How to provide type hint for a function that returns an Protocol subclass in Python?

If a function returns a subclass of a Protocol, what is the recommended type-hint for the return type of that function? The following is a simplified piece of code for representation from typing import Protocol, Type from abc import…
StevinWilson
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How to make Pylance understand Pydantic's `allow_population_by_field_name` for initializers?

In my current project, we are using an OpenAPI-to-TypeScript-API generator, that generates automatically typed functions for calling API endpoints via Axios. In Python, we use snake_case for our class properties, while in TypeScript we use…
Sebastian
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How to help Pylance understand dynamically added class properties

I'm using code such as this to add properties dynamically to a class: class A: def __init__(self, props) -> None: for name in props: setattr(self.__class__, name, property(lambda _: 1)) This will work as expected: A(["x"]).x…
myke
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How to add typing hints of **kwargs?

Here is an example: class A: def __init__(self, a=1, b=2, c=3): self.a = a self.b = b self.c = c class B(A): def __init__(self, d=4, **kwargs): super().__init__(**kwargs) self.d = d B adds one…
HYRY
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How does Pylance want me to compare numbers if int and literals can't be compared?

The expression random.randint(1, 10) == 5 causes my linter to report the error 'Operator "==" not supported for types "int" and "Literal[0]'. If I try to cast the comparison to an int/int one, like random.randint(1, 10) == int(5) It reports…
GreenTriangle
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Why are TypedDict types without field and with NotRequired field incompatible?

I am trying to create a few functions which will return values of different TypedDict types. Most of fields in them will be same so I want to generate base dictionary with same function in all cases. However I am getting stumped by typing this…
Matija Sirk
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Scikit-learn 1.2.0 extremely slow in VScode

Trying the last couple days to find the causing problem of a testing python file. After many tries and research I didn't find any solution. There is no problem with the extensions, I disabled every single extension and running extension except from…
HeuristicPointer
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Type hints for attributes using getattr

I'd like to forward the call of a method to another method, and have the second method's type hints show up in the first method. Probably easier to demonstrate. When an instance of the class below is called, it looks up the method with the name…
joudan
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vs code show double suggestion

Sample 1 Sample 2 VS Code intellisense shows double suggestions in python whenever I write. Is there a setting in VS Code, so I can change them to the normal state?
Manish Deswal
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