PyCharm使用autopep8按PEP8风格自动排版Python代码

时间 2019-12-06

标签 pycharm 使用 autopep8 autopep pep8 pep 风格自动排版 python 代码栏目 Python 繁體版

原文原文链接

前言

autopep8是一个将Python代码自动排版为PEP8风格的小工具。它使用pep8工具来决定代码中的哪部分须要被排版。autopep8能够修复大部分pep8工具中报告的排版问题。python

PyCharm使用autopep8按PEP8风格自动排版Python代码

更新记录

2018年12月27日 - 初稿git

阅读原文 - https://wsgzao.github.io/post...github

扩展阅读express

autopep8 - https://pypi.python.org/pypi/...bash

autopep8简介

使用 autopep8 前咱们有必要先了解下 PEP 8 -- Style Guide for Python Code

autopep8 automatically formats Python code to conform to the PEP 8 style guide. It uses the pycodestyle utility to determine what parts of the code needs to be formatted. autopep8 is capable of fixing most of the formatting issues that can be reported by pycodestyle.app

https://www.python.org/dev/pe...less

https://pypi.python.org/pypi/...ide

安装和使用autopep8

autopep8是一个开源的命令行工具，它可以将Python代码自动格式化为PEP8风格。autopep8使用pycodestyle工具来决定代码中的哪部分须要被格式化，这可以修复大部分pycodestyle工具中报告的排版问题。autopep8自己也是一个Python语言编写的工具，所以，咱们能够直接使用pip进行安装：函数

pip install autopep8
autopep8 --in-place optparse.py 

# To modify a file in place (with aggressive level 2):
autopep8 --in-place --aggressive --aggressive <filename>

usage: autopep8 [-h] [--version] [-v] [-d] [-i] [--global-config filename]
                [--ignore-local-config] [-r] [-j n] [-p n] [-a]
                [--experimental] [--exclude globs] [--list-fixes]
                [--ignore errors] [--select errors] [--max-line-length n]
                [--line-range line line] [--hang-closing] [--exit-code]
                [files [files ...]]

Automatically formats Python code to conform to the PEP 8 style guide.

positional arguments:
  files                 files to format or '-' for standard in

optional arguments:
  -h, --help            show this help message and exit
  --version             show program's version number and exit
  -v, --verbose         print verbose messages; multiple -v result in more
                        verbose messages
  -d, --diff            print the diff for the fixed source
  -i, --in-place        make changes to files in place
  --global-config filename
                        path to a global pep8 config file; if this file does
                        not exist then this is ignored (default:
                        ~/.config/pep8)
  --ignore-local-config
                        don't look for and apply local config files; if not
                        passed, defaults are updated with any config files in
                        the project's root directory
  -r, --recursive       run recursively over directories; must be used with
                        --in-place or --diff
  -j n, --jobs n        number of parallel jobs; match CPU count if value is
                        less than 1
  -p n, --pep8-passes n
                        maximum number of additional pep8 passes (default:
                        infinite)
  -a, --aggressive      enable non-whitespace changes; multiple -a result in
                        more aggressive changes
  --experimental        enable experimental fixes
  --exclude globs       exclude file/directory names that match these comma-
                        separated globs
  --list-fixes          list codes for fixes; used by --ignore and --select
  --ignore errors       do not fix these errors/warnings (default:
                        E226,E24,W50,W690)
  --select errors       fix only these errors/warnings (e.g. E4,W)
  --max-line-length n   set maximum allowed line length (default: 79)
  --line-range line line, --range line line
                        only fix errors found within this inclusive range of
                        line numbers (e.g. 1 99); line numbers are indexed at
                        1
  --hang-closing        hang-closing option passed to pycodestyle
  --exit-code           change to behavior of exit code. default behavior of
                        return value, 0 is no differences, 1 is error exit.
                        return 2 when add this option. 2 is exists
                        differences.

--in-place相似于sed命令的-i选项，若是不包含--in-place选项，则会将autopep8格式化之后的代码直接输出到控制台。咱们可使用这种方式检查autopep8的修改，使用--in-place则会直接将结果保存到源文件中。工具

咱们来看一个完整的例子，本例中使用的代码以下：

import os, sys  
 
def main():  
    print [item for item in os.listdir('.') if item.endswith('.py')];  
    print sys.version  
 
if __name__ == '__main__':  
    main()

这段代码存在三个问题：

导入的时候，应该每一行只导入一个包；
包导入和函数定义之间应该空两行；
Python代码末尾不须要分号。

接下来，咱们将使用pycodestyple检查这段代码，而后使用autopep8将代码格式化成符合PEP 8风格的代码。

使用pycodestyle检查代码可检测到代码中有三个地方不符合PEP 8规范，以下所示：

pycodestyle hello.py  
hello.py:1:10: E401 multiple imports on one line  
hello.py:3:1: E302 expected 2 blank lines, found 1  
hello.py:4:69: E703 statement ends with a semicolon

使用autopep8格式可以转换Python代码。在这个例子中，autopep8顺利地帮咱们修复了全部问题，以下所示：

$ autopep8 hello.py  
import os  
import sys  
 
 
def main():  
    print [item for item in os.listdir('.') if item.endswith('.py')]  
    print sys.version  
 
 
if __name__ == '__main__':  
    main()

这个时候若是查看源文件的话，会发现仍是和原来同样，并无修正为符合PEP 8规范的代码。前面说过，不指定--in-place选项，只会将结果输出到命令行。若是咱们使用--in-place选项，将不会有任何输出，autopep8会直接修改源文件。

$ autopep8 --in-place hello.py

autopep8还存在--aggressive选项，使用该选项会执行更多实质性的更改，能够屡次使用以达到更佳的效果。

以官网为例咱们编写一个test_autopep8.py

Before running autopep8.

import math, sys;

def example1():
    ####This is a long comment. This should be wrapped to fit within 72 characters.
    some_tuple=(   1,2, 3,'a'  );
    some_variable={'long':'Long code lines should be wrapped within 79 characters.',
    'other':[math.pi, 100,200,300,9876543210,'This is a long string that goes on'],
    'more':{'inner':'This whole logical line should be wrapped.',some_tuple:[1,
    20,300,40000,500000000,60000000000000000]}}
    return (some_tuple, some_variable)
def example2(): return {'has_key() is deprecated':True}.has_key({'f':2}.has_key(''));
class Example3(   object ):
    def __init__    ( self, bar ):
     #Comments should have a space after the hash.
     if bar : bar+=1;  bar=bar* bar   ; return bar
     else:
                    some_string = """
                       Indentation in multiline strings should not be touched.
Only actual code should be reindented.
"""
                    return (sys.path, some_string)

After running autopep8.

import math
import sys


def example1():
    # This is a long comment. This should be wrapped to fit within 72
    # characters.
    some_tuple = (1, 2, 3, 'a')
    some_variable = {
        'long': 'Long code lines should be wrapped within 79 characters.',
        'other': [
            math.pi,
            100,
            200,
            300,
            9876543210,
            'This is a long string that goes on'],
        'more': {
            'inner': 'This whole logical line should be wrapped.',
            some_tuple: [
                1,
                20,
                300,
                40000,
                500000000,
                60000000000000000]}}
    return (some_tuple, some_variable)


def example2(): return ('' in {'f': 2}) in {'has_key() is deprecated': True}


class Example3(object):
    def __init__(self, bar):
        # Comments should have a space after the hash.
        if bar:
            bar += 1
            bar = bar * bar
            return bar
        else:
            some_string = """
                       Indentation in multiline strings should not be touched.
Only actual code should be reindented.
"""
            return (sys.path, some_string)

autopep8能够修复的问题

autopep8 fixes the following issues reported by pycodestyle:

https://github.com/PyCQA/pyco...

E101 - Reindent all lines.
E11  - Fix indentation.
E121 - Fix indentation to be a multiple of four.
E122 - Add absent indentation for hanging indentation.
E123 - Align closing bracket to match opening bracket.
E124 - Align closing bracket to match visual indentation.
E125 - Indent to distinguish line from next logical line.
E126 - Fix over-indented hanging indentation.
E127 - Fix visual indentation.
E128 - Fix visual indentation.
E129 - Fix visual indentation.
E131 - Fix hanging indent for unaligned continuation line.
E133 - Fix missing indentation for closing bracket.
E20  - Remove extraneous whitespace.
E211 - Remove extraneous whitespace.
E22  - Fix extraneous whitespace around keywords.
E224 - Remove extraneous whitespace around operator.
E225 - Fix missing whitespace around operator.
E226 - Fix missing whitespace around arithmetic operator.
E227 - Fix missing whitespace around bitwise/shift operator.
E228 - Fix missing whitespace around modulo operator.
E231 - Add missing whitespace.
E241 - Fix extraneous whitespace around keywords.
E242 - Remove extraneous whitespace around operator.
E251 - Remove whitespace around parameter '=' sign.
E252 - Missing whitespace around parameter equals.
E26  - Fix spacing after comment hash for inline comments.
E265 - Fix spacing after comment hash for block comments.
E266 - Fix too many leading '#' for block comments.
E27  - Fix extraneous whitespace around keywords.
E301 - Add missing blank line.
E302 - Add missing 2 blank lines.
E303 - Remove extra blank lines.
E304 - Remove blank line following function decorator.
E305 - Expected 2 blank lines after end of function or class.
E306 - Expected 1 blank line before a nested definition.
E401 - Put imports on separate lines.
E402 - Fix module level import not at top of file
E501 - Try to make lines fit within --max-line-length characters.
E502 - Remove extraneous escape of newline.
E701 - Put colon-separated compound statement on separate lines.
E70  - Put semicolon-separated compound statement on separate lines.
E711 - Fix comparison with None.
E712 - Fix comparison with boolean.
E713 - Use 'not in' for test for membership.
E714 - Use 'is not' test for object identity.
E721 - Use "isinstance()" instead of comparing types directly.
E722 - Fix bare except.
E731 - Use a def when use do not assign a lambda expression.
W291 - Remove trailing whitespace.
W292 - Add a single newline at the end of the file.
W293 - Remove trailing whitespace on blank line.
W391 - Remove trailing blank lines.
W503 - Fix line break before binary operator.
W504 - Fix line break after binary operator.
W601 - Use "in" rather than "has_key()".
W602 - Fix deprecated form of raising exception.
W603 - Use "!=" instead of "<>"
W604 - Use "repr()" instead of backticks.
W605 - Fix invalid escape sequence 'x'.
W690 - Fix various deprecated code (via lib2to3).

Pycharm安装autopep8

pip安装autopep8: pip install autopep8

PyCharm -> Preferences -> Tools -> Extends Tools -> 点击+加号

Name: autopep8
Tools settings:

Programs: autopep8
Parameters: --in-place --aggressive --aggressive $FilePath$
Working directory: $ProjectFileDir$
Advanced Options -> Output Filters: $FILE_PATH$\:$LINE$\:$COLUMN$\:.*

Python之禅

最后以Python之禅做为结束语

wangao@wangao-MAC  ~  python3
Python 3.7.1 (default, Nov  6 2018, 18:46:03)
[Clang 10.0.0 (clang-1000.11.45.5)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import this
The Zen of Python, by Tim Peters

Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Readability counts.
Special cases aren't special enough to break the rules.
Although practicality beats purity.
Errors should never pass silently.
Unless explicitly silenced.
In the face of ambiguity, refuse the temptation to guess.
There should be one-- and preferably only one --obvious way to do it.
Although that way may not be obvious at first unless you're Dutch.
Now is better than never.
Although never is often better than *right* now.
If the implementation is hard to explain, it's a bad idea.
If the implementation is easy to explain, it may be a good idea.
Namespaces are one honking great idea -- let's do more of those!

翻译

美优于丑

明确优于隐晦（1）

简单优于复杂

复杂也好过繁复（2）

扁平优于嵌套

稀疏优于拥挤

可读性很重要（3）

当然代码实用与否比洁癖更重要，

咱们觉得的特例也每每没有特殊到必须打破上述规则的程度

除非刻意地静默，

不然不要无端忽视异常（4）

若是遇到模棱两可的逻辑，请不要自做聪明地瞎猜。

应该提供一种，且最好只提供一种，一目了然的解决方案

固然这是无法一蹴而就的，除非你是荷兰人（5）

当然，马上着手好过永远不作。

然而，永远不作也好过不审慎思考一撸袖子就莽着干

若是你的实现很难解释，它就必定不是个好主意

即便你的实现简单到爆，它也有多是个好办法

命名空间大法好，不搞不是地球人！

注释

该引入的包一个一个列出来不要合并；不要用星号；不要在方法里藏意想不到的的反作用，等等等等。还一个例子，另一种著名的软件设计原则 Convention over Configuration（约定优于配置）若是作得不谨慎就会违背这条
SO: 必要的复杂逻辑是不免的，而繁复啰嗦的代码是不可接受的
Readability counts 不能翻译成可读性计数啊喂
实操中不少人不注意 catch 完就 log 一下就无论了，这样很差。软件界通常都讲 Let it fail，学名为 Fail-fast 法则。简而言之就是整个项目周期中越早暴露的问题，其修复成本越低
本文做者 Tim peters 解释说这里的荷兰人指的是 Python 的做者 Guido van Rossum