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Python PEP8 程式碼規範常見問題及解決方法

之前一直用 Python IDLE 寫程式碼,最近換成 PyCharm 寫程式碼總是會出現波浪號,這才瞭解到 Python 的 PEP8 程式碼規範,所以將常見的 PEP8 程式碼規範問題和解決方法記錄一下,學習一下,遇到了再持續更新,養成良好的習慣,編寫規範的程式碼!

PEP的全稱是Python Enhancement Proposals,其中Enhancement是增強改進的意思,Proposals則可譯為提案或建議書,所以合起來,比較常見的翻譯是Python增強提案或Python改進建議書。


  • PEP 8: no newline at end of file
    解決方法:程式碼末尾需要另起一行,游標移到最後回車即可

  • PEP 8: indentation is not a multiple of four
    解決方法:縮排不是4的倍數,檢查縮排

  • PEP 8: over-indented
    解決方法:過度縮排,檢查縮排

  • PEP 8: missing whitespace after’,’
    解決方法:逗號後面少了空格,新增空格即可,類似還有分號或者冒號後面少了空格

  • PEP 8: multiple imports on one line
    解決方法:不要在一句 import 中引用多個庫,舉例:import socket, urllib.error最好寫成:import socket import urllib.error

  • PEP 8: blank line at end of line
    解決方法:程式碼末尾行多了空格,刪除空格即可

  • PEP 8: at least two spaces before inline comment
    解決方法:程式碼與註釋之間至少要有兩個空格

  • PEP 8: block comment should start with ‘#’
    解決方法:註釋要以#加一個空格開始

  • PEP 8: inline comment should start with ‘#’
    解決方法:註釋要以#加一個空格開始

  • PEP 8: module level import not at top of file


    解決方法:import不在檔案的最上面,可能之前還有其它程式碼

  • PEP 8: expected 2 blank lines,found 0
    解決方法:需要兩條空白行,新增兩個空白行即可

  • PEP 8: function name should be lowercase
    解決方法:函式名改成小寫即可

  • PEP 8: missing whitespace around operator
    解決方法:操作符(’=’、’>’、’<'等)前後缺少空格,加上即可

  • PEP 8: unexpected spaces around keyword / parameter equals
    解決方法:關鍵字/引數等號周圍出現意外空格,去掉空格即可

  • PEP 8: multiple statements on one line (colon)
    解決方法:多行語句寫到一行了,比如:if x == 2: print('OK')要分成兩行寫

  • PEP 8: line too long (82 > 79 characters)
    解決方法:超過了每行的最大長度限制79

  • PEP 8: Simplify chained comparison
    可簡化連鎖比較(例如:if a >= 0 and a <= 9: 可以簡寫為:if 0 <= a <= 9:


如果想要選擇性忽略PEP8程式碼風格的警告資訊可以使用以下方法:(養成良好的習慣,編寫規範的程式碼!不推薦忽略!)

①將滑鼠移到出現警告資訊的地方,按 alt+Enter,選擇忽略(Ignore)這個錯誤即可:

②依次選擇 File - Settings - Editor - Inspections,在 Python下找到 PEP8 coding style violation 選項,在右下角的 Ignore errors 裡點選加號可以新增需要忽略的警告資訊ID(ID資訊見後面附錄),例如想要忽略indentation contains mixed spaces and tabs這個警告,只需要新增其ID:E101 即可

附錄:全部警告資訊以及對應的ID,官方地址:https://pep8.readthedocs.io/en/latest/intro.html#error-codes

codesample 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