treyhunner

"""
Code based on talk by David Beazley's PyCon Israel keynote in 2017

Watch the talk at https://www.youtube.com/watch?v=Je8TcRQcUgA

Usage::

    from contract import Base, PositiveInteger

    dx: PositiveInteger

treyhunner

import re
import unittest


def splitlines(string, keepends=False):
    lines = re.findall('(.*\n|.+$)', string)
    return lines if keepends else [x.rstrip('\n') for x in lines]


def split(string):

treyhunner

"""
Results:

multiple_update: 33 ms
copy_and_update: 27 ms
dict_constructor: 29 ms
kwargs_hack: 33 ms
dict_comprehension: 33 ms
concatenate_items: 81 ms
union_items: 81 ms

treyhunner

>>> from collections import ChainMap
>>> user_context = {'name': "Trey", 'website': "http://treyhunner.com"}
>>> global_context = {'name': "Anonymous User", 'page_name': "Profile Page"}
>>> context = ChainMap({}, user_context, global_context)
>>> context['name']
'Trey'
>>> user_context['name'] = "Guido"
>>> context['name']
'Guido'

treyhunner

>>> from collections import ChainMap
>>> user_context = {'name': "Trey", 'website': "http://treyhunner.com"}
>>> global_context = {'name': "Anonymous User", 'page_name': "Profile Page"}
>>> context = ChainMap({}, user_context, global_context)
>>> context['page_name'] = "About Page"
>>> context['page_name']
'About Page'
>>> del context['page_name']
>>> context['page_name']
'Profile Page'

treyhunner

If we have a for loop that converts one list to another list using a transformation for each element:

doubled_numbers = []
for n in numbers:
    doubled_numbers.append(n * 2)

We can make that into a list comprehension by copy-pasting the assignment, the append value, and the for clause:

treyhunner

"""
Test performance of these counting methods:

- count_if_else: Set to 1 if not yet seen and increment otherwise
- count_if: Set to 0 if not yet seen, then increment regardless of containment
- count_exception: Attempt to increment and set to 1 if KeyError caught
- count_setdefault: Set default value to 0, then increment
- count_fromkeys: Create dict with necessary keys set to 0, then increment each
- count_set_and_comprehension: Create dict of items and counts using a set
- count_defaultdict: Increment count, automatically setting unseen values to 0

treyhunner

var something = goGetSomething();
var anotherThing = goGetAnotherThing();

Promise.all([
  something,
  anotherThing
]).then(function() {
  return doAnotherThing();
}).then(function() {
  return lastThing();

treyhunner

Japanese

[Kula Sushi][]

• Uber-modern gamified conveyor belt sushi
• Eat 100% nigiri. It's really cheap there. Rolls are just okay.

[Chopstix][] (katsu and curries)

• Katsu Don

treyhunner

Drop your code and go

• http://jsfiddle.net/
• http://jsbin.com/
• http://codepen.io/