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PEP-8 cheatsheet
#! /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
Seriously, use flake8. with
is awesome!
See 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.
def bar(cls):
"""Use cls!"""
# a 79-char ruler:
# 34567891123456789212345678931234567894123456789512345678961234567897123456789
Common naming convention names:
# Newline at end of file

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@RichardBronosky RichardBronosky commented May 5, 2020

My new favorite reference is


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@maxoralbay maxoralbay commented Jul 13, 2020

thank bro


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@GoldenKimchee GoldenKimchee commented Mar 26, 2021

nice guide!

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