PythonPEP8代码规范常见问题及解决⽅法
之前⼀直⽤ Python IDLE 写代码，最近换成 PyCharm 写代码总是会出现波浪号，这才了解到 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，学习⼀下，遇到了再持续更新，养成良好的习惯，编写规范的代码！
PEP的全称是Python Enhancement Proposals，其中Enhancement是增强改进的意思，Proposals则可译为提案或建议书，所以合起来，⽐较常见的翻译是Python增强提案或Python改进建议书。
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, 最好写成：import socket
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彼岸花的英文
PEP 8: function name should be lowerca
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
长袖衬衫
附录：全部警告信息以及对应的ID，官⽅地址：adthedocs.io/en/latest/intro.html#error-codes
code sample message
E1Indentation
E101indentation contains mixed spaces and tabs
E111indentation is not a multiple of four
E112expected an indented block
E113unexpected indentation
E114indentation is not a multiple of four (comment)
E115expected an indented block (comment)
E116unexpected indentation (comment)
E117over-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 indentiframe
E129 (^)visually indented line with same indent as next logical line
E131 (^)continuation line unaligned for hanging indent
E133 (*)closing bracket is missing indentation
E2Whitespace
E201whitespace after ‘(‘
E202whitespace before ‘)’
E203whitespace before ‘:’
E211whitespace before ‘(‘
E221multiple spaces before operator
E222multiple spaces after operator
E223tab before operator
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E224tab after operator
E225missing whitespace around operator
E226 (*)missing whitespace around arithmetic operator
E227missing whitespace around bitwi or shift operator
6599E228missing whitespace around modulo operator
E231missing whitespace after ‘,’, ‘;’, or ‘:’
E241 (*)multiple spaces after ‘,’
E242 (*)tab after ‘,’
E251unexpected spaces around keyword / parameter equals
E261at least two spaces before inline comment
E262inline comment should start with ‘# ‘
E265block comment should start with ‘# ‘
E266too many leading ‘#’ for block comment
E271multiple spaces after keyword
E272multiple spaces before keyword
E273tab after keyword
E274tab before keyword
E275missing whitespace after keyword
code sample message
E3Blank line
E301expected 1 blank line, found 0
E302expected 2 blank lines, found 0
E303too many blank lines (3)
E304blank lines found after function decorator
E305expected 2 blank lines after end of function or class
E306expected 1 blank line before a nested definition
E4Import
E401multiple imports on one line
E402module level import not at top of file
nightwish主唱tofelE5Line length
E501 (^)line too long (82 > 79 characters)
E502the backslash is redundant between brackets
E7Statement
E701multiple statements on one line (colon)
E702multiple statements on one line (micolon)
E703statement ends with a micolon
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:’
E713test for membership should be ‘not in’
E714test for object identity should be ‘is not’
E721 (^)do not compare types, u ‘isinstance()’
E722do not u bare except, specify exception instead
E731do not assign a lambda expression, u a def
E741do not u variables named ‘l’, ‘O’, or ‘I’
E742do not define class named ‘l’, ‘O’, or ‘I’
E743do not define functions named ‘l’, ‘O’, or ‘I’
E9Runtime
上海学雅思E901SyntaxError or IndentationError
E902IOError
W1Indentation warning
W191indentation contains tabs
netbookW2Whitespace warning
W291trailing whitespace
W292no newline at end of file
谢谢英文
W293blank line contains whitespace
W3Blank line warning
W391blank line at end of file
W5Line break warning
W503 (*)line break before binary operator
W504 (*)line break after binary operator
W505 (*^)doc line too long (82 > 79 characters) W6Deprecation warning
W601.has_key() is deprecated, u ‘in’
W602deprecated form of raising exception
W603‘<>’ is deprecated, u ‘!=’
W604backticks are deprecated, u ‘repr()’
W605invalid escape quence ‘x’
W606‘async’ and ‘await’ are rerved keywords starting with Python 3.7
