A newline at the end of a file does not mean that there needs to be an empty line. Your editor may not show this to you but the raw bytes would look like:
# your python code
def foo():n
return barn
If you don’t have the last n there then you will see W391. You seem to be doing
Edited to fix the last example.
@davidaames —
Could you provide some sample code where this is an issue? Thanks.
Hey, I seem to be having this issue as well, with this sample code:
raise Exception('Error: Incorrect new dag flows on line '
+ str(i))
Since this error is highly whitespace-sensitive, I don’t think it can be reproduced with simple code blocks as those are stripped. Please upload files.
That said, I suspect that the initial problem was that the end of the file looked as follows:
# your python code
def foo():n
return barn
n
Note that the last line here is not empty but has 4 spaces. This should raise W391. It was then attempted to fix the error by removing the last newline, but that left the four spaces in the now last line, which caused W292 to be raised.
As a workaround in the meantime, I have a bit in my editor(vim) config(.vimrc) that strips trailing whitespace whenever a buffer is saved. That might help you (@justinkterry) in the short term, if you use vim and are ok with your editor cleaning whitespace up for you:
function! TrimTrailingWhitespace() :%s/s+$//e endfunction autocmd BufWritePre *.py :call TrimTrailingWhitespace()
or more concisely:
autocmd BufWritePre *.py :%s/s+$//e " Trim trailing whitespace
W391 appears to supercede W292.
$ echo -n "a = 1" > file.py | pycodestyle file.py
file.py:1:1: W391 blank line at end of file
Seems like W292 should be raised first.
Hmmm, for what it’s worth, it seems like Vim inserts the newline at the end of the file, but it doesn’t look like there is a newline. I wonder if this is what was happening with the OP?
It took me quite a while to believe that I actually deserved to get W391, but when I hexdump -C /the/file | tail, it was true! The last two bytes were 0a 0a.
This is the file I use:
# -*- coding: utf-8 -*-
"""Function to sanitise paths."""
from pathvalidate import sanitize_filename
import os
def sanitise(*paths):
return os.path.join(*[sanitize_filename(x) for x in paths])
The last line does have a [W292] warning on it. Flake8 passes fine.
Running hexdump, get:
hexdump -C sanitise.py | tail
00000040 70 61 74 68 76 61 6c 69 64 61 74 65 20 69 6d 70 |pathvalidate imp|
00000050 6f 72 74 20 73 61 6e 69 74 69 7a 65 5f 66 69 6c |ort sanitize_fil|
00000060 65 6e 61 6d 65 0a 69 6d 70 6f 72 74 20 6f 73 0a |ename.import os.|
00000070 0a 0a 64 65 66 20 73 61 6e 69 74 69 73 65 28 2a |..def sanitise(*|
00000080 70 61 74 68 73 29 3a 0a 20 20 20 20 72 65 74 75 |paths):. retu|
00000090 72 6e 20 6f 73 2e 70 61 74 68 2e 6a 6f 69 6e 28 |rn os.path.join(|
000000a0 2a 5b 73 61 6e 69 74 69 7a 65 5f 66 69 6c 65 6e |*[sanitize_filen|
000000b0 61 6d 65 28 78 29 20 66 6f 72 20 78 20 69 6e 20 |ame(x) for x in |
000000c0 70 61 74 68 73 5d 29 0a |paths]).|
000000c8
This is what I see on screen:
OS: Centos (7.6.1810), neovim (0.3.2), and neovim-qt (master)…
What happens when you run pycodestyle sanitise.py from the command line? This could be a problem in the vim intergation.
What happens when you run pycodestyle sanitise.py from the command line? This could be a problem in the vim intergation.
HA! the one thing I did not try. It returns 0, no output whatsoever.
I can’t reproduce this (nor @bsmoliak’s example) on the latest version:
$ pycodestyle --version 2.5.0 $ echo -n "a = 1" > file.py | pycodestyle file.py file.py:1:6: W292 no newline at end of file
I’m having trouble understanding what «No newline at end of file» means exactly.
The error is pointing to the last line
Can someone help explain to me why I’m getting this invalid error and offer a solution to solve it. Thanks
1 Answer 1
It means exactly what it says. There is no recognizable newline at the end of the file. The last character is the ) . or maybe a TAB , or SPACE , or a line terminator for a different platform.
Solution: open the file in an editor, add a newline at the end, save and close the file.
I’ve tried that, I had a new line after it and I get «blank line contains whitespace» error.
So what you had was a line consisting of white space (SPACE or TAB characters) followed by a newline. Use your editor to get rid of that line.
The style checker wants the last line of the file to end with the newline character, and to have no trailing whitespace on that line.
Почему важно всегда ставить символ переноса строки в конце текстовых файлов?
Иногда при просмотре диффов коммитов через git log или git diff можно заметить следующий вывод:
Или на GitHub в интерфейсе для просмотра диффов:
Почему это так важно, что Git и GitHub предупреждают нас об этом? Давайте разберемся.
Что такое символ переноса строки?
Что может быть проще, чем текстовый файл? Просто текстовые данные — как хранятся на диске, так и отображаются. На самом деле правительство нам врёт всё немного сложнее.
Оффтопик про управляющие символы ASCII
Не все символы, которые содержатся в текстовых файлах, имеют визуальное представление. Такие символы ещё называют «управляющими», и к ним относятся, например:
- нулевой символ ( x00 , ) — часто используется для кодирования конца строки в памяти; т.е. программа считывает символы из памяти по одному до тех пор, пока не встретит нулевой символ, и тогда строка считается завершённой;
- табуляция ( x09 , t ) — используется для выравнивания данных по границе столбца, так что это выглядит как таблица;
- перевод строки ( x0a , n ) — используется для разделения текстовых данных на отдельные строки;
- возврат каретки ( x0d , r ) — переместить курсор в начало строки;
- возврат на один символ ( x08 , b ) — переместить курсор на один символ назад;
- звонок ( x07 , a ) — если набрать этот символ в терминале, то будет бибикающий символ; именно так консольные программы, типа vim , бибикают на пользователей; .
Многие эти символы пришли к нам из эпохи печатных машинок, поэтому у них такие странные названия. И действительно, в контексте печатной машинки или принтера такие операции, как перевод строки (сместить лист бумаги вверх так, чтобы печатающая головка попала на следующую строку), возврат каретки (переместить печатающую головку в крайнее левое положение) и возврат на один символ назад, обретают смысл. При помощи возврата на один символ назад создавались жирные символы (печатаешь символ, возвращаешься назад и печатаешь его ещё раз) и буквы с диакритическими знаками, такие как à или ã (печатаешь символ, возвращаешься назад и печатаешь апостроф или тильду). Но зачем печатной машинке бибикалка?
Сегодня многие из этих символов потеряли смысл, но некоторые до сих пор выполняют функцию, схожую с исходной.
Текстовые редакторы отображают текстовые файлы в некоем адаптированном виде, преобразуя непечатаемые символы, например, переносы строк и табуляции преобразуются в настоящие отдельные строки или выравнивающие отступы.
Для набора символа переноса строки достаточно нажать клавишу «Enter», но на разных платформах этот символ закодируется по-разному:
- в Unix-совместимых системах (включая современные версии macOS) используется один символ перевода строки ( LF );
- в Windows используется сразу два символа — возврат каретки ( CR ) и перевод строки ( LF );
- в очень старых версиях Mac OS (до 2001 года) использовался один символ CR .
Как видите, Windows точнее всего эмулирует поведение печатной машинки.
В языках программирования символ новой строки часто кодируют при помощи бэкслэш-последовательностей, таких как n или rn . Нужно понимать разницу между такой последовательностью и настоящим символом переноса строки. Если в редакторе в файле *.txt просто набрать n и сохранить, то вы получите ровно то, что написали. Символом переноса строки оно не станет. Нужно что-то, что заменит эти бэкслэш-последовательности на настоящие символы переноса строки (например, компилятор или интерпретатор языка программирования).
Почему перенос строки в конце файла важен?
Согласно определению из стандарта POSIX, который тоже пришёл к нам из эпохи печатных машинок:
Строка — это последовательность из нуля или более символов, не являющихся символом новой строки, и терминирующего символа новой строки.
Почему важен этот стандарт? Возможен миллиард способов реализовать одно и то же, и только благодаря стандартам, таким как POSIX, мы имеем сейчас огромное количество качественного ПО, которое не конфликтует друг с другом.
Т.е. если вы не ставите символ переноса строки в конце строки, то формально по стандарту такая строка не является валидной. Множество утилит из Unix, которыми я пользуюсь каждый день, написано в согласии с этим стандартом, и они просто не могут правильно обрабатывать такие «сломанные» строки.
Давайте, например, через Python создадим такой файл со сломанными строками:
Сколько по-вашему в этом файле строк? Три? Давайте посмотрим, что об этом файле думает утилита wc , которая с флагом -l умеет считать количество строк в файле:
Упс! wc нашла только 2 строки!
Давайте создадим еще один файл:
И попробуем теперь склеить два созданных файла при помощи утилиты cat :
Название cat — это сокращение от «конкатенация», и никак не связано с котиками. А жаль.
И опять какой-то странный результат! В большинстве случаев это не то, чего вы бы ожидали, но вполне возможны ситуации, когда вам нужен именно такой результат. Именно поэтому утилита cat не может самостоятельно вставлять отсутствующие символы переноса строки, иначе это сделало бы её поведение неконсистентным.
Это только пара примеров, но многие другие утилиты, которые работают с текстом (например, diff , grep , sed ), имеют такие же проблемы. Собственно говоря, это даже не проблемы, а их задокументированное поведение.
Ещё доводы:
- при дозаписи содержимого в конец файла без переноса строки получится некрасивый дифф — будет изменена последняя строка (хотя на ней всего лишь добавился символ переноса);
- файл с переносом строки и без переноса строки — это два разных файла; для diff и git diff единственный способ отобразить разницу между ними — это напечатать сообщение об отсутствии символа переноса строки;
- согласно стандарту языка C (до 2014 года), непустые файлы с исходным кодом должны заканчиваться символом переноса строки.
Настраиваем редактор
Самый простой способ перестать думать о пустых строках и начать жить — это настроить свой текстовый редактор или IDE на автоматическое добавление символа переноса строки в конец файлов:
- PyCharm и другие IDE JetBrains: Settings > Editor > General > Ensure an empty line at the end of a file on Save ;
- VS Code: «files.insertFinalNewline»: true .
Для других редакторов смотрите настройку здесь.
Кстати, если вы пользуетесь форматтером black , то у меня хорошие новости — он всегда добавляет перенос строки в конец всех файлов *.py .
Заключение
Возможно, такая маленькая деталь, как перенос строки в конце файла и не кажется очень важной, а тема вообще кажется спорной, но боюсь, что у нас нет другого выбора, кроме как принять это правило за данность и просто выработать привычку (или настроить инструментарий) всегда ставить символ новой строки в любых текстовых файлах, даже если этого не требуется явно. Это считается распространённой хорошей практикой, и как минимум убережёт вас и ваших коллег от всяких неожиданных эффектов при работе с утилитами Unix.
В текстовом редакторе это выглядит как лишняя пустая строка в конце файла:
W391 blank line at end of file introduces —> W292 no newline at end of file #365
The text was updated successfully, but these errors were encountered:
IanLee1521 commented Jan 3, 2015
Could you provide some sample code where this is an issue? Thanks.
jkterry1 commented Mar 15, 2018
Hey, I seem to be having this issue as well, with this sample code:
FichteFoll commented Mar 15, 2018 •
Since this error is highly whitespace-sensitive, I don’t think it can be reproduced with simple code blocks as those are stripped. Please upload files.
That said, I suspect that the initial problem was that the end of the file looked as follows:
Note that the last line here is not empty but has 4 spaces. This should raise W391. It was then attempted to fix the error by removing the last newline, but that left the four spaces in the now last line, which caused W292 to be raised.
hoylemd commented Mar 16, 2018 •
As a workaround in the meantime, I have a bit in my editor(vim) config(.vimrc) that strips trailing whitespace whenever a buffer is saved. That might help you (@justinkterry) in the short term, if you use vim and are ok with your editor cleaning whitespace up for you:
or more concisely:
bsmoliak commented Jan 4, 2019
W391 appears to supercede W292.
Seems like W292 should be raised first.
codypiersall commented Jan 16, 2019
Hmmm, for what it’s worth, it seems like Vim inserts the newline at the end of the file, but it doesn’t look like there is a newline. I wonder if this is what was happening with the OP?
It took me quite a while to believe that I actually deserved to get W391, but when I hexdump -C /the/file | tail , it was true! The last two bytes were 0a 0a .
What is PEP 8 ?
Before going into details of PEP 8 the first thing that we need to understand that what exactly is PEP and what is 8 signifies in PEP 8.
PEP contains the index of all Python Enhancement Proposals, known as PEPs. This is an aggregate of documents which explains about information, new features, process and environment settings for python community.
PEP numbers are assigned by the PEP editors, and once assigned are never changed. It signifies the document number.
PEP 8 means Python Enhancement Proposal document number 8 which details about Style Guide for Python Code. This style guide evolves over time as additional conventions are identified and past conventions are rendered obsolete by changes in the language itself.
Although there is no restriction of using all the PEP 8 rule these are good to have as it helps in making code consistency and improve code readability.
You can install, upgrade, uninstall pycodestyle.py (formerly called pep8)with these commands:
$ pip install pycodestyle
$ pip install --upgrade pycodestyle
$ pip uninstall pycodestyle
Enter fullscreen mode
Exit fullscreen mode
Pycodestyle(formerly called pep8) Usage
For demo purpose lets created a test python file with a function to find the max between two numbers find_max.py having content as —
def find_max_number(a:int,b:int)->int:
return a if a>b else b
if __name__ == "__main__":
find_max_number(10,15)
Executing pycodestyle for this file
pycodestyle find_max.py
find_max.py:3:22: E231 missing whitespace after ':'
find_max.py:3:26: E231 missing whitespace after ','
find_max.py:3:28: E231 missing whitespace after ':'
find_max.py:3:33: E225 missing whitespace around operator
find_max.py:4:18: E225 missing whitespace around operator
find_max.py:6:1: E305 expected 2 blank lines after class or function definition, found 1
find_max.py:7:23: E231 missing whitespace after ','
find_max.py:7:27: W292 no newline at end of file
Enter fullscreen mode
Exit fullscreen mode
In this case we have 8 violations.
As you see above, it outputs the file name which has violations, location, error code and that content.
In order to get output summary of PEP 8 violations we need run the following command pycodestyle --statistics --qq <file_name>
pycodestyle --statistics -qq find_max.py
2 E225 missing whitespace around operator
4 E231 missing whitespace after ':'
1 E305 expected 2 blank lines after class or function definition, found 1
1 W292 no newline at end of file
Enter fullscreen mode
Exit fullscreen mode
In order to have more details on the voilation we need to use show-source option as pycodestyle --show-source <file_name>
pycodestyle --show-source find_max.py
find_max.py:3:22: E231 missing whitespace after ':'
def find_max_number(a:int,b:int)->int:
^
find_max.py:3:26: E231 missing whitespace after ','
def find_max_number(a:int,b:int)->int:
^
find_max.py:3:28: E231 missing whitespace after ':'
def find_max_number(a:int,b:int)->int:
^
find_max.py:3:33: E225 missing whitespace around operator
def find_max_number(a:int,b:int)->int:
^
find_max.py:4:18: E225 missing whitespace around operator
return a if a>b else b
^
find_max.py:6:1: E305 expected 2 blank lines after class or function definition, found 1
if __name__ == "__main__":
^
find_max.py:7:23: E231 missing whitespace after ','
find_max_number(10,15)
^
find_max.py:7:27: W292 no newline at end of file
find_max_number(10,15)
^
Enter fullscreen mode
Exit fullscreen mode
Moreover you can see the description of how to fix. This is --show-pep8 option.
pycodestyle --show-pep8 find_max.py
find_max.py:3:22: E231 missing whitespace after ':'
Each comma, semicolon or colon should be followed by whitespace.
Okay: [a, b]
Okay: (3,)
Okay: a[1:4]
Okay: a[:4]
Okay: a[1:]
Okay: a[1:4:2]
E231: ['a','b']
E231: foo(bar,baz)
E231: [{'a':'b'}]
find_max.py:3:26: E231 missing whitespace after ','
Each comma, semicolon or colon should be followed by whitespace.
Okay: [a, b]
Okay: (3,)
Okay: a[1:4]
Okay: a[:4]
Okay: a[1:]
Okay: a[1:4:2]
E231: ['a','b']
E231: foo(bar,baz)
E231: [{'a':'b'}]
find_max.py:3:28: E231 missing whitespace after ':'
Each comma, semicolon or colon should be followed by whitespace.
Okay: [a, b]
Okay: (3,)
Okay: a[1:4]
Okay: a[:4]
Okay: a[1:]
Okay: a[1:4:2]
E231: ['a','b']
E231: foo(bar,baz)
E231: [{'a':'b'}]
find_max.py:3:33: E225 missing whitespace around operator
Surround operators with a single space on either side.
- Always surround these binary operators with a single space on
either side: assignment (=), augmented assignment (+=, -= etc.),
comparisons (==, <, >, !=, <=, >=, in, not in, is, is not),
Booleans (and, or, not).
- If operators with different priorities are used, consider adding
whitespace around the operators with the lowest priorities.
Okay: i = i + 1
Okay: submitted += 1
Okay: x = x * 2 - 1
Okay: hypot2 = x * x + y * y
Okay: c = (a + b) * (a - b)
Okay: foo(bar, key='word', *args, **kwargs)
Okay: alpha[:-i]
E225: i=i+1
E225: submitted +=1
E225: x = x /2 - 1
E225: z = x **y
E225: z = 1and 1
E226: c = (a+b) * (a-b)
E226: hypot2 = x*x + y*y
E227: c = a|b
E228: msg = fmt%(errno, errmsg)
find_max.py:4:18: E225 missing whitespace around operator
Surround operators with a single space on either side.
- Always surround these binary operators with a single space on
either side: assignment (=), augmented assignment (+=, -= etc.),
comparisons (==, <, >, !=, <=, >=, in, not in, is, is not),
Booleans (and, or, not).
- If operators with different priorities are used, consider adding
whitespace around the operators with the lowest priorities.
Okay: i = i + 1
Okay: submitted += 1
Okay: x = x * 2 - 1
Okay: hypot2 = x * x + y * y
Okay: c = (a + b) * (a - b)
Okay: foo(bar, key='word', *args, **kwargs)
Okay: alpha[:-i]
E225: i=i+1
E225: submitted +=1
E225: x = x /2 - 1
E225: z = x **y
E225: z = 1and 1
E226: c = (a+b) * (a-b)
E226: hypot2 = x*x + y*y
E227: c = a|b
E228: msg = fmt%(errno, errmsg)
find_max.py:6:1: E305 expected 2 blank lines after class or function definition, found 1
Separate top-level function and class definitions with two blank
lines.
Method definitions inside a class are separated by a single blank
line.
Extra blank lines may be used (sparingly) to separate groups of
related functions. Blank lines may be omitted between a bunch of
related one-liners (e.g. a set of dummy implementations).
Use blank lines in functions, sparingly, to indicate logical
sections.
Okay: def a():n passnnndef b():n pass
Okay: def a():n passnnnasync def b():n pass
Okay: def a():n passnnn# Foon# Barnndef b():n pass
Okay: default = 1nfoo = 1
Okay: classify = 1nfoo = 1
E301: class Foo:n b = 0n def bar():n pass
E302: def a():n passnndef b(n):n pass
E302: def a():n passnnasync def b(n):n pass
E303: def a():n passnnnndef b(n):n pass
E303: def a():nnnn pass
E304: @decoratornndef a():n pass
E305: def a():n passna()
E306: def a():n def b():n passn def c():n pass
find_max.py:7:23: E231 missing whitespace after ','
Each comma, semicolon or colon should be followed by whitespace.
Okay: [a, b]
Okay: (3,)
Okay: a[1:4]
Okay: a[:4]
Okay: a[1:]
Okay: a[1:4:2]
E231: ['a','b']
E231: foo(bar,baz)
E231: [{'a':'b'}]
find_max.py:7:27: W292 no newline at end of file
Trailing blank lines are superfluous.
Okay: spam(1)
W391: spam(1)n
However the last line should end with a new line (warning W292).
Enter fullscreen mode
Exit fullscreen mode
If we want to exclude specific errors and warning while running pycodestyle we can use the option -ignore and provide the comma separated values of the error codes need to be excluded.
pycodestyle - ignore=E231,E225 find_max.py
find_max.py:6:1: E305 expected 2 blank lines after class or function definition, found 1
find_max.py:7:27: W292 no newline at end of file
Enter fullscreen mode
Exit fullscreen mode
As we have put E231,E225 in the ignore list the PEP 8 violation count reduced to 2 from 8 which is without ignoring these errors.
PEP 8 Error codes
Code can either denote an error or warning in case of error codes the code start with E followed by a 3 digit number for e.g E101 and for warning code it start with E followed by a 3 digit number for e.g W191.
Below is the classification of error code based on series number.
100 series … (E1 and W1) related to indentation.
200 series … (E2 and W2) related to whitespace.
300 series … (E3 and W3) related to blank lines.
400 series … (E4 and W4) related to imports.
500 series … (E5 and W5) related to line length.
600 series … (E6 and W6) related to deprecation.
700 series … (E7) related to statements.
900 series … (E9) related to syntax errors.
You can refer to official document for more detailing on error code link.
Customization of pep8
We can customise the PEP 8 config to meet our requirement as in we might need to ignore certain errors and warning and also we want to alter the max-line-length etc.
Default user configuration file is in ‘~/.config/pycodestyle‘.
You can write the configuration file as below, this is same as option.
[pep8]
ignore = E231,E225
max-line-length = 160
Enter fullscreen mode
Exit fullscreen mode
You can specify the configuration file location by--config=<configration_file_location> .
By storing above configuration file in a certain location in respective projects, you can share it in the projects.
At the project level, a setup.cfg file or a tox.ini file is read if present (.pep8 file is also supported, but it is deprecated). If none of these files have a [pep8] section, no project specific configuration is loaded.
Commonly used PEP 8 guidelines
The PEP 8 guidelines can classified in 7 different categories as
Code Lay-out
- Use 4 spaces per indentation level.
- Use spaces not tabs python disallows mixing tabs and spaces for indentation.
- Limit all lines to a maximum of 79 characters.
- Should a line break before or after binary operator? In Python code, it is permissible to break before or after a binary operator, as long as the convention is consistent locally.
- Surround top-level function and class definitions with two blank lines.
- Code in the core Python distribution should always use UTF-8, and should not have an encoding declaration.
Imports should be grouped in the following order:
- Standard library imports.
- Related third party imports.
- Local application/library specific imports.
Wildcard imports (from import *) should be avoided.
Naming Conventions
Naming conventions are the most important pillar in maintaining the code consistency and readability there is as such no rule book to define the naming conventions but PEP 8 has recommendation that is good to follow.
- Never use the characters ‘l’ , ‘O’ , or ‘I’ (uppercase letter eye) as single character variable names. In some fonts, these characters are indistinguishable from the numerals one and zero.
- Class names should normally use the Cap Words (Camel case) convention.
- Variables and function names should have all lowercase letters and underscores to separate words.
- Constant should have all uppercase letters with words separated by underscores
- Use the suffix «Error» on your exception names (if the exception actually is an error).
- Use self for the first argument to instance methods or class methods.
String Quotes
- In Python, single-quoted strings and double-quoted strings are the same. PEP does not make a recommendation for this. Pick a rule and stick to it. When a string contains single or double quote characters, however, use the other one to avoid backslashes in the string. It improves readability.
- Whitespace in Expression and Statement
- Avoid trailing whitespace anywhere. Because it’s usually invisible, it can be confusing: e.g. a backslash followed by a space and a newline does not count as a line continuation marker.
- Always surround these binary operators with a single space on either side: assignment (=), augmented assignment (+=, -= etc.), comparisons (==, <, >, !=, <>, <=, >=, in, not in, is, is not), Booleans (and, or, not).
- Use whitespace to communicate order of operations. x = 12*y + 22*z.
- Avoid excessive whitespace immediately inside of parenthesis, brackets, or braces.
When to use trailing commas
- Trailing commas are usually optional, except they are mandatory when making a tuple of one element. For clarity, it is recommended to surround the latter in parentheses:
# Correct:
FILES = ('setup.cfg',)
# Wrong:
FILES = 'setup.cfg',
Enter fullscreen mode
Exit fullscreen mode
Programming Recommendations
- Comparisons to singletons like None should always be done with is or is not, never the equality operators.
- Use is notoperator rather than not … is for e.g if foo is not None rather than if not foo is None:
- When implementing ordering operations with rich comparisons, it is best to implement all six operations (eq, ne, lt, le, gt, ge) rather than relying on other code to only exercise a particular comparison.
- When catching exceptions, mention specific exceptions whenever possible instead of using a bare except.
- Object type comparisons should always use isinstance() instead of comparing types directly.
Comments
Each line of a block comment starts with a # and a single space.
Use inline comments only if it is unavoidable.
Write docstrings for all public modules, functions, classes, and methods.
Docstrings are not necessary for non-public methods, but you should have a comment that describes what the method does.
For more detailing on the PEP 8 guidelines please check out the official documentation PEP 8 Guidelines
Conclusion
Likewise pycodestyle there is flake8 which is also widely used for checking the code style PEP 8 guidelines in python code. It’s always better to have these plugins in the ide and everytime you save or commit it will highlight the violations.
Maintaining the code style guideline helps in better readability and code consistency. Although it’s a good to have but always prefer to have coding guidelines while writing code.
[Error record] Pycharm runs Python program error (PEP 8: W292 No Newline at End of File)
tags: Error record Python pycharm
Articles directory
- 1. Report an error message
- 2. Solution
1. Report an error message
Pycharm Run the python program to report an error:
PEP 8: W292 no newline at end of file
2. Solution
At the end of each Python file, a empty line must be added;
After the following modifications, the error disappear is resolved;
Copyright Complaint
Spam Report
Intelligent Recommendation
Introduction to PEP 8, error codes and warnings ignored
I have recently compared with Pycharm’s PEP-8. No need, really no need. After I read it, re-record the valuable content in this process. Introduction to PEP 8 PEP-8 is a Python code style guide. The a…
Backtracking-record the program that runs error, DEBUG normal
Preface I am currently doing the task of TS code stream analysis. During the test, it is found that some code streams are running normally, and some code streams will run incorrectly. So it is very li…
vue error learning Newline required at end of file but not found
Error: Newline required at end of file but not found Translation: end of the file require line breaks, but could not find E.g: This will not however given below The reason is the need to add one line …
vue reports an error — «Newline required at end of file but not found»
An error occurs in the vue project: Newline required at end of file but not found The reason is that the eslint code specification is opened in the vue project, and you need to add a line of space to …
Vue error jumping: Newline Required At End of File But Not Found.
Newline required at end of file but not found. First translate A newline is required at the end of the file, but not found. Cause Analysis Eslint’s standardization requirement, ending must have a newl…
More Recommendation
[Vue error resolution] Newline Required At End of File But Not Found
Reason for error: There is a room in the end of the file. Solve: In the last plus a line of blank….
Newline required at end of file but not found eol-last error
An error is reported in the vue project: Newline required at end of file but not found eol-last Meaning: At the end of the file a newline is required Just add a newline at the end of the file…
[Error record] Intellij ID in MAC runs the Python program error (no module named ‘numpy‘)
Articles directory 1. Report an error message 2. Solution 1. Report an error message When compiling, report an error as follows: 2. Solution This error is probably caused by Numpy-1.21.2 and Python3.1…
[Error record] Intellij ID in MAC runs the Python program error (no module named ‘threadPool’)
Articles directory 1. Report an error message 2. Solution 1. Report an error message After installing the Python plug -inimport threadpool Under the code, report the following errors; Mouse moveimport…
Pycharm references the module and reports an error, but the program runs normally
Recently I learned that there was a problem when importing modules with pycharm, and I solved it by searching for information. Take some necessary notes, one is to consolidate the knowledge you have l…