Lightning talk I held at https://pyconweb.com/ about how my Python idioms changed over the years, and how trying to write smart (but unreadable) code is bad :)

1. Is this good Python?
No seriously, what do you think?
Steffen from TrustYou
@tyengineering
Lightning talk @ PyCon WEB Munich 2017

2. Just find me one element in a list
def is_what_i_want(el):
# something
filter(is_what_i_want, els)[0]

3. Well, if there actually is one
try:
el = filter(is_what_i_want, els)[0]
except IndexError:
el = None

4. Use next(), dream of find_first() - JS and Java 8 have them …
el = next((el for el in els
if is_what_i_want(el)), None)

5. Renaming a dictionary key (because Mongo)
data["new_name"] = data["old_name"]
del data["old_name"]

6. What do you think, readable?
data["new_name"] = data.pop("old_name")

7. I zip()
corpus = list(izip_longest(*[corpus] * batch))

8. “Defensive programming” - gotta be sure …
name = None if user is None else user["name"]
# meh …
name = (user or {}).get("name")
# getting hard to read …

9. Short-circuiting
user = None
name = user and user["name"]
# What's in "name"?
user = ()
# How about now?

10. (Or just use JSON schema)
http://json-schema.org/

11. Collections.defaultdict + recursion to the rescue
def tree():
return defaultdict(tree)
data["props"]["prop"] = # stuff …

12. Whoops
data["porps"] # oops, now "porps"
exists

13. Metaclasses
● Customize class creation
● Customize object creation (__init__ initializes, doesn’t create)
● Confuse readers
some_task = VacuumTable(table_name="users")
another_task = VacuumTable(table_name="users")
assert some_task is another_task