Python PEP8 code convention

PEP 은 무엇인가?

PEP 8 -- Style Guide for Python Code

PEP:	8
Title:	Style Guide for Python Code
Author:	Guido van Rossum <guido at python.org>, Barry Warsaw <barry at python.org>, Nick Coghlan <ncoghlan at gmail.com>
Status:	Active
Type:	Process
Created:	05-Jul-2001
Post-History:	05-Jul-2001, 01-Aug-2013

PEP8은  Python Enhancement Proposals (PEP) 의 8 번째 내용으로, 더 나은 파이썬 코드를 작성하기 위한 하나의 코딩 규약 (Style Guide for Python Code)입니다. (https://www.python.org/dev/peps/pep-0008/)

Python PEP8 code convention cheat sheet

아래 파이썬 코드는 PEP8 style 을 활용한 코딩 예입니다. 일종의 cheat sheet로 이 코드만 알면 PEP8 에서 지향하는 파이썬 코딩 스타일의 대부분을 알 수 있습니다!

내용을 간단하게 요약하면 아래와 같습니다.

1. 모듈과 패키지 이름은 짧고 lower_case_with_underscore 이다. 

2. 다른 모듈에서 import 할 때 보일 필요가 없는 함수, 변수는 변수명 앞에 _를 추가한다. 

3. 상수는 A_CONSTANT 

4. 함수는 naming_convention

5. 클래스는 NamingConvention

6. 한 라인의 길이가 79 길이가 넘지 않도록 한다. (이것은 대략적인 A4 용지 사이즈이다.)

#! /usr/bin/env python

# -*- coding: utf-8 -*-

"""This module's docstring summary line.


This is a multi-line docstring. Paragraphs are separated with blank lines.

Lines conform to 79-column limit.


Module and packages names should be short, lower_case_with_underscores.

Notice that this in not PEP8-cheatsheet.py


Seriously, use flake8. Atom.io with https://atom.io/packages/linter-flake8

is awesome!


See http://www.python.org/dev/peps/pep-0008/ for more PEP-8 details

"""





import os  # STD lib imports first

import sys  # alphabetical



import some_third_party_lib  # 3rd party stuff next

import some_third_party_other_lib  # alphabetical



import local_stuff  # local stuff last

import more_local_stuff

import dont_import_two, modules_in_one_line  # IMPORTANT!

from pyflakes_cannot_handle import *  # and there are other reasons it should be avoided # noqa

# Using # noqa in the line above avoids flake8 warnings about line length!





_a_global_var = 2  # so it won't get imported by 'from foo import *'

_b_global_var = 3



A_CONSTANT = 'ugh.'





# 2 empty lines between top-level funcs + classes

def naming_convention():

    """Write docstrings for ALL public classes, funcs and methods.



    Functions use snake_case.

    """

    if x == 4:  # x is blue <== USEFUL 1-liner comment (2 spaces before #)

        x, y = y, x  # inverse x and y <== USELESS COMMENT (1 space after #)

    c = (a + b) * (a - b)  # operator spacing should improve readability.

    dict['key'] = dict[0] = {'x': 2, 'cat': 'not a dog'}





class NamingConvention(object):

    """First line of a docstring is short and next to the quotes.



    Class and exception names are CapWords.



    Closing quotes are on their own line

    """



    a = 2

    b = 4

    _internal_variable = 3

    class_ = 'foo'  # trailing underscore to avoid conflict with builtin



    # this will trigger name mangling to further discourage use from outside

    # this is also very useful if you intend your class to be subclassed, and

    # the children might also use the same var name for something else; e.g.

    # for simple variables like 'a' above. Name mangling will ensure that

    # *your* a and the children's a will not collide.

    __internal_var = 4



    # NEVER use double leading and trailing underscores for your own names

    __nooooooodontdoit__ = 0



    # don't call anything (because some fonts are hard to distiguish):

    l = 1

    O = 2

    I = 3



    # some examples of how to wrap code to conform to 79-columns limit:

    def __init__(self, width, height,

                 color='black', emphasis=None, highlight=0):

        if width == 0 and height == 0 and \

           color == 'red' and emphasis == 'strong' or \

           highlight > 100:

            raise ValueError('sorry, you lose')

        if width == 0 and height == 0 and (color == 'red' or

                                           emphasis is None):

            raise ValueError("I don't think so -- values are %s, %s" %

                             (width, height))

        Blob.__init__(self, width, height,

                      color, emphasis, highlight)



    # empty lines within method to enhance readability; no set rule

    short_foo_dict = {'loooooooooooooooooooong_element_name': 'cat',

                      'other_element': 'dog'}



    long_foo_dict_with_many_elements = {

        'foo': 'cat',

        'bar': 'dog'

    }



    # 1 empty line between in-class def'ns

    def foo_method(self, x, y=None):

        """Method and function names are lower_case_with_underscores.



        Always use self as first arg.

        """

        pass



    @classmethod

    def bar(cls):

        """Use cls!"""

        pass



# a 79-char ruler:

# 34567891123456789212345678931234567894123456789512345678961234567897123456789

"""

Common naming convention names:

snake_case

MACRO_CASE

camelCase

CapWords

"""


# Newline at end of file

출처 - https://gist.github.com/RichardBronosky/454964087739a449da04