treyhunner, 7 months ago to python

So lambda expressions allows us to write shorter code by defining a function on the same line that we pass that function to sorted.

Read the full article: What are lambda expressions?
▸ https://trey.io/uuFX1k

#Python

treyhunner, 7 months ago to random

You know you've been adulting too much when you realize you have strong opinions about the best and worst pieces of hold music. 😬☎️

BajoranEngineer, 7 months ago to random

Do yall buy trip insurance?

treyhunner, 7 months ago to python

Need to merge two dictionaries together in #Python?

>>> user = {'name': "Trey", 'website': "https://treyhunner.com/"}
>>> defaults = {'name': "Anonymous User", 'page_name': "Profile Page"}

You'll sometimes see this hack in old code:

>>> merged = dict(defaults, **user)

But that only works if the keys are all strings.

This works (added in Python 3.5):

>>> merged = {**defaults, **user}

But on Python 3.9 and above, this works too!

>>> merged = defaults | user

https://treyhunner.com/2016/02/how-to-merge-dictionaries-in-python/

treyhunner, 7 months ago to python

Flattening a list-of-lists (or iterable-of-iterables) in #Python?

Take your pick.

1️⃣ nested loops

names = []
for g in groups:
for n in g:
names.append(n)

2️⃣ extend in a loop

names = []
for g in groups:
names.extend(g)

or +=:
names += g

3️⃣ comprehension or generator:

names = [
n
for g in groups
for n in g
]

4️⃣ chain.from_iterable

from itertools import chain
names = chain.from_iterable(groups)

More details plus one "bad" way: https://pym.dev/flatten-a-list-in-python/

AlSweigart, 7 months ago to random

deleted_by_author

treyhunner, 7 months ago to python

Some #Python Morsels exercises were inspired by real problems. 🏗️

Some help me teach:

• countdown: a timer I use in EVERY live training
• vote: count student votes during trainings
• make_file: used in many exercise test files
• zero: helps me resize my screen properly

Some are tools I needed 🧰

• bullet points: parse WorkFlowy exports
• dmath: date math CLI
• reformat_diary: translated OhLife exports
• reconcile: analyzed finance files
• jot: my daily journaling
• plan_meeting: timezones

treyhunner, 8 months ago to python

The Python Morsels web app & pastebin tool now support Python 3.12: https://www.pythonmorsels.com/history/278/

Also the solution walk-throughs for all Python Morsels exercises now discuss Python 3.12 features, where relevant.

Want to try out some interesting Python 3.12 features in your web browser?

Play with this #Python paste: https://www.pythonmorsels.com/p/2vxxa/

treyhunner, 8 months ago to python

What's a #Python feature you wish existed but doesn't? 🤔

It can even be something others would think is absurd. 🛸

Dream big! 💭

treyhunner, 8 months ago to linguistics

"loanword is a calque and calque is a loanword"

I'm a sucker for edutainment videos with a clever punchline

#linguistics

https://www.youtube.com/watch?v=TFpzps-DCb0

treyhunner, 7 months ago to python

A #Python context manager class

class C:
def init(self, x):
self.x = x
def enter(self):
print("☂️")
return self # for "as"
def exit(self, cls, exc, tb):
print("🌂")

optionally return truthy value to suppress exception re-raising

And here's how to use that context manager:

>>> with C("🥳") as c: # "c" becomes the enter return value
... print(c.x)
...
☂️
🥳
🌂

More:
• https://pym.dev/what-is-a-context-manager/
• https://pym.dev/creating-a-context-manager/

treyhunner, 7 months ago to python

Dictionary keys and set items must be hashable in #Python.

But what does "hashable" actually mean?

And what does hashability actually do for us?

That's the topic of this week's Python Morsels video.

https://youtu.be/DKR0-PDWb20?si=gs4x40ABbe1H7duM

treyhunner, 7 months ago to python

Data read from outside the Python process is read as raw bytes.

When opening files in text mode, #Python decodes bytes to text using a charcter encoding (utf-8 by default). In many other cases, Python doesn't guess an encoding.

This week's screencast is on encoding & decoding bytes.

https://youtu.be/rD4ZXzeoJHo?si=Ydp4SYgC_nU5iQ35

treyhunner, 8 months ago to python

Does your #Python object have a "length"? 📏

It might make sense to support the built-in len function.

You just need a len method! 🪄

https://youtu.be/vnhDr2Dq4s8?feature=shared

treyhunner, 7 months ago to python

In #Python, looping over an iterable one way does the same thing as looping another way.

>>> name = "Trey"

Looping with a *:

>>> print(*name)
T r e y

With functions:

>>> list(name)
['T', 'r', 'e', 'y']
>>> " ".join(name)
'T r e y'

With tuple unpacking:

>>> a, b, c, d = name
>>> c
'e'

When you loop over "object X" one way, you'll see the same behavior when you loop a different way.

An iterable is an iterable, no matter the form of looping.

https://www.pythonmorsels.com/iterable/

treyhunner, 8 months ago to python

This week's video is on customizing how the == operator works on your Python objects.

You can use == between any 2 objects in #Python, but "False" will be the typical response.

You can make a eq method to give your objects a more natural sense of equality. 📐

https://youtu.be/PYQ8kOVA2zw?feature=shared

treyhunner, 7 months ago to python

Python sequence shortcuts

first = seq[0]
last = seq[-1]

first_n = seq[:n]
last_n = seq[-n:]
middle = seq[1:-1]

first, *middle, last = seq
reversed = seq[::-1]

lazy_reversed = reversed(seq)

These work on lists, tuples, range objects, and any other list-like object in Python.

Here's a script that shows off these #Python features: https://pym.dev/p/2e6fc/

That script demonstrates these sequence features:

⭐ Indexing
⭐ Slicing
⭐ Extended tuple unpacking
⭐ Reversing lazily

treyhunner, 8 months ago to python

Have a #Python object that you'd like to support index/key lookups (like["this"])?

Add a getitem method to your class.

https://youtu.be/R8Gun_58-Nk?si=yi8ANhpOw5VgskkA