SpaceVim/docs/layers/lang/python.md

---
title: "SpaceVim lang#python layer"
description: "This layer is for Python development, provides autocompletion, syntax checking, and code formatting for Python files."
---

# [Available Layers](../../) >> lang#python

<!-- vim-markdown-toc GFM -->

- [Description](#description)
- [Installation](#installation)
  - [Enable language layer](#enable-language-layer)
  - [Language tools](#language-tools)
- [Layer options](#layer-options)
- [Key bindings](#key-bindings)
  - [Jump to definition](#jump-to-definition)
  - [Code generation](#code-generation)
  - [Code Coverage](#code-coverage)
  - [Text objects and motions](#text-objects-and-motions)
  - [Inferior REPL process](#inferior-repl-process)
  - [Running current script](#running-current-script)
  - [Testing](#testing)
  - [Refactoring](#refactoring)

<!-- vim-markdown-toc -->

## Description

This layer is for Python development.

## Installation

### Enable language layer

The `lang#python` layer is not loaded by default, to use this layer,
you need to add following snippet into your spacevim configuration file.

```toml
[[layers]]
  name = "lang#python"
```

### Language tools

- **syntax checking:**

  `checker` layer provides syntax checking feature, and for Python it uses the `pylint` package:

  ```sh
  pip install --user pylint
  ```

- **code formatting:**

  The default key binding for formatting the current buffer is `SPC b f`,
  and you need to install `yapf`.

  ```sh
  pip install --user yapf
  ```

  To use another tool as the format command, for example `black`,
  change the neoformat option in bootstrap function.

  ```viml
  let g:neoformat_python_black = {
      \ 'exe': 'black',
      \ 'stdin': 1,
      \ 'args': ['-q', '-'],
      \ }
  let g:neoformat_enabled_python = ['black']
  ```

- **code formatting:**

  The default formatter for python is [yapf](https://github.com/google/yapf).

  ```
  pip install --user yapf
  ```

  To be able to suppress unused imports easily, install [autoflake](https://github.com/myint/autoflake):

  ```
  pip install --user autoflake
  ```

  To be able to sort your imports, install [isort](https://github.com/timothycrosley/isort)

  ```
  pip install --user isort
  ```

- **code coverage:**

  To be able to show code coverage, install coverage.py

  ```
  pip install --user coverage
  ```

## Layer options

- `python_file_head`: Default file head when create new python file.

  By default, when create a new python file, SpaceVim will insert file head automatically.
  to change the file head, use `python_file_head` option:

  ```toml
  [[layers]]
    name = "lang#python"
    python_file_head = [
        '#!/usr/bin/env python',
        '# -*- coding: utf-8 -*-',
        '',
        ''
    ]
  ```

  When the autocomplete layer is enabled, the symbol will be completed automatically.
  By default the type info is disabled, because it is too slow. To enable type info add the following to your configuration file:

  ```toml
  [[layers]]
    name = "lang#python"
    enable_typeinfo = true
  ```

- `format_on_save`: Enable/disable file formatting when saving current python file. By default,
  it is disabled, to enable it:
  ```toml
  [[layers]]
      name = 'lang#python'
      format_on_save = true
  ```

- `python_interpreter`: Set the python interpreter, by default, it is `python3`. The value of this option will
  be applied to `g:neomake_python_python_exe` and code runner.
  ```toml
  [[layers]]
      name = 'lang#python'
      python_interpreter = 'D:\scoop\shims\python.exe'
  ```

- `enabled_linters`: Set the default linters for python language, by default it is `['python']`. You can change
  it to `['python', 'pylint']`.
  ```toml
  [[layers]]
    name = 'lang#python'
    enabled_linters = ['python', 'pylint']
  ```

## Key bindings

### Jump to definition

| Mode   | Key Bindings | Description                                                |
| ------ | ------------ | ---------------------------------------------------------- |
| normal | `g d`        | Jump to the definition position of the symbol under cursor |

### Code generation

| Mode   | Key Binding | Description        |
| ------ | ----------- | ------------------ |
| normal | `SPC l g d` | Generate docstring |

### Code Coverage

| Mode   | Key Binding | Description       |
| ------ | ----------- | ----------------- |
| normal | `SPC l c r` | coverager report  |
| normal | `SPC l c s` | coverager show    |
| normal | `SPC l c e` | coverager session |
| normal | `SPC l c f` | coverager refresh |

### Text objects and motions

This layer contains [vim-pythonsense](https://github.com/jeetsukumaran/vim-pythonsense)
which provides text objects and motions for Python classes, methods, functions, and doc strings.

| Text Objects | Descriptions                |
| ------------ | --------------------------- |
| `ac`         | Outer class text object     |
| `ic`         | Inner class text object     |
| `af`         | Inner function text object  |
| `if`         | Inner function text object  |
| `ad`         | Inner docstring text object |
| `id`         | Inner docstring text object |

### Inferior REPL process

Start a Python or iPython inferior REPL process with `SPC l s i`. If `ipython` is available in system executable search paths, `ipython` will be used to launch Python shell; otherwise, default `python` interpreter will be used. You may change your system executable search path by activating a virtual environment.

Send code to inferior process commands:

| Key Bindings | Descriptions                                     |
| ------------ | ------------------------------------------------ |
| `SPC l s b`  | send buffer and keep code buffer focused         |
| `SPC l s l`  | send line and keep code buffer focused           |
| `SPC l s s`  | send selection text and keep code buffer focused |

### Running current script

To run a Python script, you can press `SPC l r` to run the current file without losing focus, and the result will be shown in a runner buffer.

### Testing

### Refactoring

| Key Bindings | Descriptions                         |
| ------------ | ------------------------------------ |
| `SPC l i r`  | remove unused imports with autoflake |
| `SPC l i s`  | sort imports with isort              |