Because you spend much of your development time in the code editor,Python support in Visual Studio provides functionality to help you be more productive. Features include IntelliSense syntax highlighting, autocompletion, signature help, method overrides, search, and navigation.

The code editor is integrated with theInteractive window in Visual Studio. As you work, it's easy to exchange code between the two windows. For more information, seeTutorial Step 3: Use the Interactive REPL window andUse the Interactive window - Send to Interactive command.

Outlining helps you stay focused on particular sections of your code. For general documentation on editing code in Visual Studio, seeFeatures of the code editor.

The Visual StudioObject Browser lets you inspect Python classes defined in each module and the functions defined in those classes. You can access this feature on theView menu or by using the keyboard shortcutCtrl+Alt+J.

Use IntelliSense features

IntelliSense providescompletions,signature help,quick info, andcode coloring. Visual Studio 2017 versions 15.7 and later also supporttype hints.

To improve performance, IntelliSense in Visual Studio 2017 version 15.5 and earlier depends on a completion database generated for each Python environment in your project. You might need to refresh your database if you add, remove, or update packages. Database status is shown in thePython Environments window (a companion ofSolution Explorer) on theIntelliSense tab. For more information, seeEnvironments window reference.

Visual Studio 2017 version 15.6 and later uses a different means to provide IntelliSense completions that aren't dependent on the database.

Completions

Completions appear as statements, identifiers, and other words that can be appropriately entered at the current location in the editor. Intellisense populates the list of options based on context and filters incorrect or distracting items. Completions are often triggered by entering different statements (such asimport) and operators (including a period), but they can appear at anytime by selecting the keyboard shortcutCtrl+J +Space.

When a completion list is open, you can search for the completion you want by using the arrow keys, the mouse, or by continuing to type. As you type more letters, the list is further filtered to show likely completions. You can also use shortcuts such as:

• Type letters that aren't at the start of the name, such as 'parse' to find 'argparse'
• Type only letters that are at the start of words, such as 'abc' to find 'AbstractBaseClass' or 'air' to find 'as_integer_ratio'
• Skip letters, such as 'b64' to find 'base64'

Here are some examples:

Member completions appear automatically when you type a period after a variable or value, along with the methods and attributes of the potential types. If a variable can be more than one type, the list includes all possibilities from all types. Extra information is shown to indicate which types support each completion. When all possible types support a completion, no annotation is shown.

By default, "dunder" members (members beginning and ending with a double underscore) aren't shown. In general, such members shouldn't be accessed directly. If you need to use a dunder, type the leading double underscore to add these completions to the list:

Theimport andfrom ... import statements display a list of modules that can be imported. Thefrom ... import statement produces a list that includes members that can be imported from the specified module.

Theraise andexcept statements display lists of classes likely to be error types. The list might not include all user-defined exceptions, but it helps you find suitable built-in exceptions quickly:

Selecting@ symbol (at) starts a decorator and shows potential decorators. Many of these items aren't usable as decorators. Check the library documentation to determine which decorator to use.

For more information, seeOptions - completion results.

Type hints

Type hints are available in Visual Studio 2017 version 15.7 and later.

"Type hints" in Python 3.5+ (PEP 484 (python.org) is an annotation syntax for functions and classes that indicate the types of arguments, return values, and class attributes. IntelliSense displays type hints when you hover over functions calls, arguments, and variables that have those annotations.

In the following example, theVector class is declared as the typeList[float], and thescale function contains type hints for both its arguments and return value. Hovering over a call to that function shows the type hints:

In the next example, you can see how the annotated attributes of theEmployee class appear in the IntelliSense completion popup for an attribute:

It's also helpful to validate type hints throughout your project because errors don't normally appear until run time. For this purpose, Visual Studio integrates the industry standard Mypy tool through the context menu commandPython >Run Mypy inSolution Explorer:

Running the command prompts you to install the Mypy package, if needed. Visual Studio then runs Mypy to validate type hints in every Python file in the project. Errors appear in the Visual StudioError List window. Selecting an item in the window navigates to the appropriate line in your code.

As a simple example, the following function definition contains a type hint to indicate that theinput argument is typestr, whereas the call to that function attempts to pass an integer:

def commas_to_colons(input: str):    items = input.split(',')    items = [x.strip() for x in items]    return ':'.join(items)commas_to_colons(1)

Using theRun Mypy command on this code generates the following error:

Signature help

When writing code that calls a function, signature help appears when you type the opening parenthesis(. It displays available documentation and parameter information. You can access signature help with the keyboard shortcutCtrl+Shift+Space inside a function call. The information displayed depends on the documentation strings in the function's source code, but includes any default values.

Quick info

Hovering the mouse pointer over an identifier displays a Quick Info tooltip. Depending on the identifier, Quick Info might display the potential values or types, any available documentation, return types, and definition locations:

Code coloring

Code coloring uses information from code analysis to color variables, statements, and other parts of your code. Variables that refer to modules or classes might be shown in a different color than functions or other values. Parameter names might appear in a different color than local or global variables. By default, functions aren't shown in bold.

Insert code snippets

Code snippets are fragments of code that can be inserted into your files by using a keyboard shortcut and selectingTab. You can also use theEdit >IntelliSense >Insert Snippet andSurround With commands, selectPython, and then select the desired snippet.

For example,class is a shortcut for a code snippet that inserts a class definition. You see the snippet appear in the autocompletion list when you typeclass:

SelectingTab generates the rest of the class. You can then type over the name and bases list, move between the highlighted fields withTab, and selectEnter to begin typing the body.

Menu commands

When you use theEdit >IntelliSense >Insert Code Snippet menu command, you first selectPython, and then select the desired snippet:

TheEdit >IntelliSense >Surround With command places the current selection in the text editor inside a chosen structural element. Suppose you had a piece of code like the following example:

sum = 0for x in range(1, 100):    sum = sum + x

Selecting this code and choosing theSurround With command displays a list of available snippets. Choosingdef from the snippet list places the selected code within a function definition. You can use theTab key to navigate between the highlighted function name and arguments:

Examine available snippets

You can see the available code snippets in theCode Snippets Manager. Access this feature fromTools >Code Snippets Manager and selectPython as the language:

To create your own snippets, seeWalkthrough: Create a code snippet.

If you write a great code snippet that you'd like to share, feel free to post it in a gist andlet us know. We might be able to include it in a future release of Visual Studio.

Navigate your code

Python support in Visual Studio provides several ways to quickly navigate within your code, including libraries for which the source code is available. You can find libraries with source code for thenavigation bar,Go To Definition,Go To, andFind All References commands. You can also use the Visual StudioObject Browser.

Navigation bar

The navigation bar is displayed at the top of each editor window and includes a two-level list of definitions. The left dropdown contains top-level class and function definitions in the current file. The right dropdown displays a list of definitions within the scope shown in the left. As you move around in the editor, the lists update to show your current context, and you can also select an entry from these lists to jump directly to.

Go To Definition

TheGo To Definition command quickly jumps from the use of an identifier (such as a function name, class, or variable), to the location of the source code definition. To invoke the command, right-click an identifier and selectGo To Definition or place the caret in the identifier and selectF12. The command works across your code and external libraries where the source code is available. If library source code isn't available,Go To Definition jumps to the relevantimport statement for a module reference or displays an error.

Go To

TheEdit >Go To command (Ctrl+,) displays a search box in the editor where you can type any string and see possible matches in your code that defines a function, class, or variable containing that string. This feature provides a similar capability asGo To Definition but without having to locate a use of an identifier.

To navigate to the definition of that identifier, double-click any name or select the name with arrow keys followed byEnter.

Find All References

TheFind All References feature is a helpful way of discovering where any given identifier is both defined and used, including imports and assignments. To invoke the command, right-click an identifier and selectFind All References, or place the caret in the identifier and selectShift+F12. Double-clicking an item in the list navigates to its location.

Related content

• Format Python code
• Refactor Python code
• Use a linter