This document discusses the Zen of Python philosophy and PEP 8 style guide for writing Python code. It begins by introducing the author and their background. It then explains how to view the Zen of Python principles by importing the "this" module. Several of the Zen principles are listed and explained. The document continues by covering PEP 8 guidelines for indentation, whitespace, comments and other stylistic choices. It provides examples of preferred versus non-preferred coding styles. It concludes by mentioning tools for linting and formatting Python code and provides additional resources for learning more.

1. Zen and the Art of Python
Clayton Parker - Pythology 101
Zen and the Art of Python - Clayton Parker - Pythology 101

2. Who am I?
Director of Engineering at Six Feet Up
claytron on the internets

3. The Zen of Python
and
The Python Style Guide
(PEP8)

4. The Zen of Python
$ python -m this
>>> import this

5. The Zen of Python
$ python -m this
The Zen of Python, by Tim Peters
Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Readability counts.
Special cases aren't special enough to break the rules.
Although practicality beats purity.
Errors should never pass silently.
Unless explicitly silenced.
In the face of ambiguity, refuse the temptation to guess.
There should be one-- and preferably only one --obvious way to do it.
Although that way may not be obvious at first unless you're Dutch.
Now is better than never.
Although never is often better than *right* now.
If the implementation is hard to explain, it's a bad idea.
If the implementation is easy to explain, it may be a good idea.
Namespaces are one honking great idea -- let's do more of those!

6. Beautiful is better than ugly

7. Readability Counts

8. PEP 8
We have a set of rules for that!

9. PEP 8
Prevailing style wins

10. Comments
# Comments start with a space after the comment symbol. Use complete
# sentences and proper grammar when writing comments. Comments should
# be in English unless you are certain the readers will *not* be
# English speaking.
# Long flowing text should be kept to under 72 columns like above.
x = 5 # Use inline comments sparingly.

11. Indentation
4 space indents
Tabs only if the prevailing style
Never mix tabs and spaces!

12. Whitespace

13. important_var = 5
awesome_var = 15
awesome_var+=10
my_dict ={ 'spam':'eggs','ham':'parrot'}
my_list=[3, 2,1]
another_list = [8, 4,5,6 ]
extra_list=my_list+another_list
sorted ( combined_list,reverse = True)

14. important_var = 5
awesome_var = 15
awesome_var += 10
my_dict = {'spam': 'eggs', 'ham': 'parrot'}
my_list = [3, 2, 1]
another_list = [8, 4, 5, 6]
extra_list = my_list + another_list
sorted(combined_list, reverse=True)

15. Max Line Length
A hotly debated subject!

16. things = ['overwrite', 'photobathic', 'tranquillization', 'resiny', 'runt', 'Siganus']
extra_special_things = [thing for thing in extra_shiny_things if thing == 'elpidite']
################################################################ 79 columns --|

17. ################################################################ 79 columns --|
things = [
'overwrite',
'photobathic',
'tranquillization',
'resiny',
'runt',
'Siganus',
]
extra_special_things = [
thing
for thing in extra_shiny_things
if thing == 'elpidite'
]

18. ################################################################ 79 columns --|
if event.new_state.id == 'offline' and (state == 'published' or state == 'external'):
workflow.doActionFor(obj, 'reject', workflow='custom_workflow', comment='Reject')

19. ################################################################ 79 columns --|
offline = event.new_state.id == 'offline'
published = state in ['published', 'external']
if offline and published:
workflow.doActionFor(
obj,
'reject',
workflow='custom_workflow',
comment='Reject content automatically',
)

20. ################################################################ 79 columns --|
long_string = "Lorem ipsum dolor sit amet, consectetur adipiscing. Cras cursus elit."

21. ################################################################ 79 columns --|
long_string = (
"Lorem ipsum dolor sit amet, consectetur adipiscing."
"Cras cursus elit."
)

22. Explicit is better than implicit

23. import os, sys
from my.package import *

24. import os
import sys
from my.package import Octopus, Blowfish

25. There should be one-- and
preferably only one --obvious
way to do it

26. # Bad
type(obj) is type(1)
# Good
isinstance(obj, int)

27. # Bad
my_variable == None
# Good
my_variable is None

28. # Bad
not len(my_list) > 0
# Good
not my_list

29. # Bad
boolean_value == False
# Good
not boolean_value

30. Flat is better than nested

31. for item in items:
if some_check(item):
# do some magic
if another_check(item):
# more magic
operate_on(item)

32. for item in items:
if not some_check(item):
continue
if not another_check(item):
continue
# do some magic
# more magic
operate_on(item)

33. aws_region = None
for k,v in query_response.items():
if k == 'entry_list':
for i in v:
for k, v2 in i.items():
if k == 'name_value_list':
if isinstance(v2, dict):
for k2, v3 in v2.items():
if k2 == 'aws_region':
aws_region = v3['value']

34. aws_region = None
entries = query_response.get('entry_list', {})
values = entries.get('name_value_list', {})
if isinstance(values, dict):
aws_region = values.get('aws_region', {}).get('value', None)

35. Tools
flake8 - Combination of pep8 and pyflakes
PyLint / Frosted - More in-depth linting of code
autopep8 - Automatic PEP8 conformance

36. Links
The Zen of Python - PEP 20
Zen discussed on Stackoverflow
The Python Style Guide - PEP 8
Writing Idiomatic Python Book

37. Questions?