Python PEP8 代码规范常见问题及解决方法
PyCharm 写代码总是会出现波浪号，了解到 Python 的 PEP8 代码规范，所以将常见的 PEP8 代码规范问题和解决方法记录一下。
PEP 8: no newline at end of file 解决方法：代码末尾需要另起一行，光标移到最后回车即可 PEP 8: indentation is not a multiple of four 解决方法：缩进不是4的倍数，检查缩进 PEP 8: over-indented 解决方法：过度缩进，检查缩进 PEP 8: missing whitespace after’,’ 解决方法：逗号后面少了空格，添加空格即可，类似还有分号或者冒号后面少了空格 PEP 8: multiple imports on one line 解决方法：不要在一句 import 中引用多个库，举例：import socket, urllib.error最好写成：import socket import urllib.error PEP 8: blank line at end of line 解决方法：代码末尾行多了空格，删除空格即可 PEP 8: at least two spaces before inline comment 解决方法：代码与注释之间至少要有两个空格 PEP 8: block comment should start with ‘#’ 解决方法：注释要以#加一个空格开始 PEP 8: inline comment should start with ‘#’ 解决方法：注释要以#加一个空格开始 PEP 8: module level import not at top of file 解决方法：import不在文件的最上面，可能之前还有其它代码 PEP 8: expected 2 blank lines，found 0 解决方法：需要两条空白行，添加两个空白行即可 PEP 8: function name should be lowercase 解决方法：函数名改成小写即可 PEP 8: missing whitespace around operator 解决方法：操作符（’=’、’>’、’<'等）前后缺少空格，加上即可 PEP 8: unexpected spaces around keyword / parameter equals 解决方法：关键字/参数等号周围出现意外空格，去掉空格即可 PEP 8: multiple statements on one line (colon) 解决方法：多行语句写到一行了，比如：if x == 2: print('OK')要分成两行写 PEP 8: line too long (82 > 79 characters) 解决方法：超过了每行的最大长度限制79 PEP 8: Simplify chained comparison 可简化连锁比较（例如：if a >= 0 and a <= 9: 可以简写为：if 0 <= a <= 9:）
如果想要选择性忽略PEP8代码风格的警告信息可以使用以下方法：（养成良好的习惯，编写规范的代码！不推荐忽略！）
①将鼠标移到出现警告信息的地方，按 alt+Enter，选择忽略（Ignore）这个错误即可： ②依次选择 File - Settings - Editor - Inspections，在 Python下找到 PEP8 coding style violation 选项，
在右下角的 Ignore errors 里点击加号可以添加需要忽略的警告信息ID（ID信息见后面附录），
例如想要忽略indentation contains mixed spaces and tabs这个警告，只需要添加其ID：E101 即可
附录：全部警告信息以及对应的ID，官方地址：https://pep8.readthedocs.io/en/latest/intro.html#error-codes
code sample message E1 Indentation E101 indentation contains mixed spaces and tabs E111 indentation is not a multiple of four E112 expected an indented block E113 unexpected indentation E114 indentation is not a multiple of four (comment) E115 expected an indented block (comment) E116 unexpected indentation (comment) E117 over-indented E121 (*^) continuation line under-indented for hanging indent E122 (^) continuation line missing indentation or outdented E123 (*) closing bracket does not match indentation of opening bracket’s line E124 (^) closing bracket does not match visual indentation E125 (^) continuation line with same indent as next logical line E126 (*^) continuation line over-indented for hanging indent E127 (^) continuation line over-indented for visual indent E128 (^) continuation line under-indented for visual indent E129 (^) visually indented line with same indent as next logical line E131 (^) continuation line unaligned for hanging indent E133 (*) closing bracket is missing indentation E2 Whitespace E201 whitespace after ‘(‘ E202 whitespace before ‘)’ E203 whitespace before ‘:’ E211 whitespace before ‘(‘ E221 multiple spaces before operator E222 multiple spaces after operator E223 tab before operator E224 tab after operator E225 missing whitespace around operator E226 (*) missing whitespace around arithmetic operator E227 missing whitespace around bitwise or shift operator E228 missing whitespace around modulo operator E231 missing whitespace after ‘,’, ‘;’, or ‘:’ E241 (*) multiple spaces after ‘,’ E242 (*) tab after ‘,’ E251 unexpected spaces around keyword / parameter equals E261 at least two spaces before inline comment E262 inline comment should start with ‘# ‘ E265 block comment should start with ‘# ‘ E266 too many leading ‘#’ for block comment E271 multiple spaces after keyword E272 multiple spaces before keyword E273 tab after keyword E274 tab before keyword E275 missing whitespace after keyword E3 Blank line E301 expected 1 blank line, found 0 E302 expected 2 blank lines, found 0 E303 too many blank lines (3) E304 blank lines found after function decorator E305 expected 2 blank lines after end of function or class E306 expected 1 blank line before a nested definition E4 Import E401 multiple imports on one line E402 module level import not at top of file E5 Line length E501 (^) line too long (82 > 79 characters) E502 the backslash is redundant between brackets E7 Statement E701 multiple statements on one line (colon) E702 multiple statements on one line (semicolon) E703 statement ends with a semicolon E704 (*) multiple statements on one line (def) E711 (^) comparison to None should be ‘if cond is None:’ E712 (^) comparison to True should be ‘if cond is True:’ or ‘if cond:’ E713 test for membership should be ‘not in’ E714 test for object identity should be ‘is not’ E721 (^) do not compare types, use ‘isinstance()’ E722 do not use bare except, specify exception instead E731 do not assign a lambda expression, use a def E741 do not use variables named ‘l’, ‘O’, or ‘I’ E742 do not define classes named ‘l’, ‘O’, or ‘I’ E743 do not define functions named ‘l’, ‘O’, or ‘I’ E9 Runtime E901 SyntaxError or IndentationError E902 IOError W1 Indentation warning W191 indentation contains tabs W2 Whitespace warning W291 trailing whitespace W292 no newline at end of file W293 blank line contains whitespace W3 Blank line warning W391 blank line at end of file W5 Line break warning W503 (*) line break before binary operator W504 (*) line break after binary operator W505 (*^) doc line too long (82 > 79 characters) W6 Deprecation warning W601 .has_key() is deprecated, use ‘in’ W602 deprecated form of raising exception W603 ‘<>’ is deprecated, use ‘!=’ W604 backticks are deprecated, use ‘repr()’ W605 invalid escape sequence ‘x’ W606 ‘async’ and ‘await’ are reserved keywords starting with Python 3.7
From：https://blog.csdn.net/qq_36759224/article/details/89304878
