PyCharm 2023.3 Help

Code completion

This section covers various techniques of context-aware code completion that allow you to speed up your coding process.

Basic completion

Basic code completion helps you complete the names of classes, methods, and keywords within the visibility scope.

When you invoke code completion, PyCharm analyzes the context and suggests the choices that are reachable from the current caret position (suggestions also include Live templates).

If basic code completion is applied to a part of a field, parameter, or variable declaration, PyCharm suggests a list of possible names depending on the item type.

Invoking Basic code completion for the second time shows the names of classes, functions, modules, and variables in the entire project, regardless of dependencies.

Invoke basic completion

  1. Start typing a name.

  2. Press Control+Space or choose Code | Code Completion | Basic from the main menu.

    The images below show basic code completion for the following cases:

    • Methods:

      Completing Method
    • Method parameters:

      Completing method parameters
    • Dictionaries:

      Completing Dicts
    • Django templates:

      Completing Filter
    • File paths completion in Python string literals:

      Path completion
      Path completion
  3. If necessary, press Control+Space for the second time (or press Control+Alt+Space).

    This shows the names of classes, functions, modules, and variables.

    Class name completion

Type-matching completion

Smart type-matching code completion filters the suggestion list and shows only the types applicable to the current context.

Invoke type-matching completion

  • Smart type-matching code completion filters the suggestion list and shows only the types applicable to the current context. To invoke type-matching completion, start typing your code and press Control+Shift+Space. Alternatively, select Code | Code Completion | Type-Matching from the main menu.

Smart type completion

Statement completion

You can create syntactically correct code constructs by using statement completion Control+Shift+Enter. It inserts the necessary syntax elements and gets you in a position where you can start typing the next statement.

Complete a method declaration

  • Start typing a method declaration and press Control+Shift+Enter after the opening parenthesis.

    PyCharm automatically completes a method declaration with the mandatory parameter self. Start typing a method declaration in a Python class, and PyCharm will insert self after the opening bracket of the parameter list. This behavior is configurable in the Smart Keys page of the editor settings.

    Statement completion for a method

Complete a code construct

  • Start typing a code construct and press Control+Shift+Enter.

    PyCharm automatically completes the construct and adds the required punctuation. The caret is placed at the next editing position.

    Completing code construct

Complete statements in collections

  • PyCharm automatically inserts a trailing comma before a line break in multiline collection literals. In dict literals, it inserts a colon between a key and a value. Press Control+Shift+Enter to invoke statement completion:

    Completing a current statement in collections

    Note that because of the language ambiguity regarding syntax of some incomplete collection literals, a colon is inserted neither after the first key of a dict literal nor after the first item of a parenthesized tuple.

Hippie completion

Hippie completion is a completion engine that analyses your text in the visible scope and generates suggestions from the current context. It helps you complete any word from any of the currently opened files.

Expand a string at caret to an existing word

  1. Type the initial string and do one of the following:

    • Press Alt+/ or choose Code | Code Completion | Cyclic Expand Word to search for matching words before the caret.

    • Press Alt+Shift+/ or choose Code | Code Completion | Cyclic Expand Word (Backward) to search for matching words after the caret and in other open files.

    The first suggested value appears, and the prototype is highlighted in the source code.

    Expand word
  2. Accept the suggestion, or hold the Alt key and keep pressing / until the desired word is found.

Postfix code completion

Postfix code completion helps you reduce backward caret jumps as you write code. You can transform an already-typed expression to a different one based on a postfix you type after the dot, the type of expression, and its context.

Enable and configure postfix completion

  • In the Settings dialog (Control+Alt+S), open Editor | General | Postfix Completion and select the Enable postfix completion checkbox.

  • Select Tab, Space, or Enter to be used for expanding postfix templates.

  • Enable/disable a particular postfix template for the selected language.

Transform a statement with a postfix

  • Type an expression and then type a postfix after a dot, for example, .if:

    def f(a): a.if

    The initial expression gets wrapped with an if statement:

    def f(a): if a:

You can disable certain postfix completion templates in the Editor | General | Postfix Completion page of the IDE settings Control+Alt+S.

You can select Tab,Space, or Enter to expand postfix templates.

You can edit the predefined postfix templates, for example, to replace a long key with a shorter one, or to expand the list of applicable expression types.

Create custom postfix templates

  1. Press Control+Alt+S to open the IDE settings and then select Editor | General | Postfix Completion.

  2. Click the Add button (the Add button) on the toolbar.

  3. In the popup menu that opens, choose the language that you need to create a postfix template for.

  4. Specify Key, a combination of symbols that will invoke the template.

  5. Select which expression types the new template will be applicable to, and type the target expression in the following format: $EXPR$ <target_expression>, for example, [x for x in $EXPR$].

    Add $END$ where you want the caret to be placed after the template is applied, for example:

    [x$END$ for x in $EXPR$]
    Create a custom postfix template
  6. To have PyCharm automatically transform the topmost applicable expression when the template is invoked, select the Apply to the topmost expression checkbox.

    Otherwise, if the checkbox is cleared, PyCharm will prompt you to choose the expression when you invoke the template.

    apply custom postfix template

F-string completion

Whenever you open a curly brace in an ordinary string literal, PyCharm provides the same completion suggestions as for an f-string. When you select one of the suggested options, the IDE automatically converts the literal into an f-string by adding a missing f prefix and a closing curly brace.

F-string completion

Auto import on module name completion

PyCharm automatically adds an import statement when you refer any module member or package in the Python code and invoke code completion. Auto-import on code completion is also applied to some popular package name aliases, such as np for numpy or pd for pandas.

Auto-import on code completion

Machine-learning-assisted code completion

PyCharm allows you to prioritize completion suggestions based on choices that other users made in similar situations.

The ML completion mechanism doesn't add any new elements but orders the elements retrieved from code. Data is not exposed anywhere; it is collected locally.

Enable ML completion

  1. Press Control+Alt+S to open the IDE settings and select Editor | General | Code Completion.

  2. Under Machine Learning Completion Ranking, enable the Sort completion suggestions based on machine learning option, and select the languages for which you want to use ML completion.

    ML-assisted completion settings

Enable relevance markers

  1. Press Control+Alt+S to open the IDE settings and select Editor | General | Code Completion.

  2. Enable the following options:

    • Mark position changes in the completion popup: use the Machine Learning ranking Up and Machine Learning ranking Down icons to indicate whether the relevance of a suggestion is increasing or decreasing and therefore the suggestion has moved up or down the suggestion list.

    • Mark the most relevant item in the completion popup: use the ML relevant proposal icon to indicate the most suitable suggestion on the list.

    The suggestion list will look as follows with the icons marking reordered and the most relevant items.

    ML completion is enabled

Full Line code completion

Full Line code completion provides suggestions as you type code in the editor. Suggestions are displayed in gray italics. To accept the suggestion, press Tab.

Full line completion

Enable Full Line completion

  1. Press Control+Alt+S to open the IDE settings and select Editor | General | Code Completion.

  2. In the Machine Learning Completion Ranking section, select Enable Full Line suggestion and make sure that Python is also selected.

    Enabling full line code completion

Configure Full Line completion

  1. Hover over the suggestion.

  2. In the popup that appears, click App expui general chevron down large and select the key that you want to use for accepting suggestions.

    To assign your own shortcut, select Custom.

    Full line code completion popup
  3. For quick access to the Full Line completion settings, click App expui general more vertical in the popup.

Configure code completion settings

To configure code completion options, go to the Editor | General | Code Completion page of the IDE settings Control+Alt+S.

You can choose the following settings:

Item

Description

Match case

Select if you want the letter case to be taken into account for completion suggestions. Choose whether you want to match the case for the first letter or for all letters.

Automatically insert single suggestions for

Automatically complete code if there's just one suggestion for basic and smart type-matching completion.

Sort suggestions alphabetically

Select if you want to sort items in the suggestion list in the alphabetical order instead of sorting them by relevance.

You can change this behavior at any time by clicking App actions more in the suggestion list and toggling the Sort by Name option.

Show suggestions as you type

Select if you want the suggestion list to be invoked automatically, without having to call completion explicitly. This option is enabled by default.

Insert selected suggestion by pressing space, dot, or other context-dependent keys

Select if you want to insert the selected suggestion by typing certain keys that depend on the language, your context, and so on.

Show the documentation popup in

Select to automatically show a popup for each item in the suggestion list with the documentation for the class, method, or field currently highlighted in the lookup list.

In the field to the right, specify the delay (in milliseconds), after which the popup should appear.

Insert parentheses automatically when applicable

If this option is enabled, PyCharm automatically inserts a pair of opening and closing parentheses when you complete a function/method.

Insert parentheses on completion is enabled

Clear the checkbox to suppress inserting parentheses automatically.

If you use an opening parentheses ( instead of Enter to apply the selected item from a completion list, parentheses will be inserted automatically no matter whether the option is turned on or off.

Insert parentheses on completion is disabled. Parentheses are still inserted on completion with an opening brace.

To use an opening parentheses ( instead of Enter to apply the selected item from a completion list, open the Settings dialog (Control+Alt+S), go to Editor | General | Code Completion, and select the Insert selected suggestion by pressing space, dot, or other context-dependent keys checkbox.

For more information, refer to Use specific keys to insert suggestions.

Completion tips and tricks

Open completion settings from the completion popup

You can quickly access code completion settings right from the completion popup.

  • Click the App actions more icon in the completion popup and select Code Completion Settings.

    Opening completion settings

After that, the Editor | General | Code Completion page of the IDE settings Control+Alt+S opens.

Narrow down the suggestion list

  • You can narrow down the suggestion list by typing any part of a word (even characters from somewhere in the middle) or invoking code completion after a dot separator . PyCharm will show suggestions that include the characters you have entered in any positions.

    This makes the use of wildcards unnecessary:

    codeCompletionWildcard.png

    In case of CamelCase or snake_case names, type the initial letters only. PyCharm automatically recognizes and matches the initial letters.

Accept a suggestion

You can accept a suggestion from the list in one of the following ways:

  • Press Enter or double-click a list item to insert it to the left of the caret.

  • Press Tab to replace the characters to the right from the caret.

  • Use Control+Shift+Enter to make the current code construct syntactically correct (balance parentheses, add missing braces and semicolons, and so on).

You can also use specific keys to insert the selected completion suggestion: go to the Editor | General | Code Completion page of the IDE settings Control+Alt+S and select the Insert the selected suggestion by pressing space, dot, or other context-dependent keys option. These keys depend on the language, your context, and so on.

View reference

  • You can use the Quick Definition view by pressing Control+Shift+I when you select an entry in the suggestion list:

    Quick definition
  • You can use the Quick Information view by pressing Control+Q when you select an entry in the suggestion list:

    Quick documentation

View code hierarchy

You can view code hierarchy when you've selected an entry from the suggestion list:

  • Control+H - view type hierarchy

  • Control+Shift+H - view method hierarchy.

Troubleshooting

If code completion doesn't work, this may be due to one of the following reasons:

  • The Power Save Mode is on (File | Power Save Mode). Turning it on minimizes power consumption of your laptop by eliminating the background operations, including error highlighting, on-the-fly inspections, and code completion.

  • Your file doesn't reside in a content root , so it doesn't get the required class definitions and resources needed for code completion.

    For more information, refer to Configuring Project Structure.

  • A file containing classes and functions that you want to appear in the completion suggestion list is marked as a plain text file.

  • External libraries that contain functions that you want to appear in the completion suggestion list are not added as dependencies or global libraries.

  • Code completion popup might not appear automatically if it takes too long to gather the completion options. For example, if the computer is busy with another task. In this case, you may still activate the completion popup manually via Ctrl+Space hotkey.

Last modified: 11 January 2024