Python Tip #40 (of 365): Use dictionaries for grouping items (by using a dictionary of lists, sets, or other data structures). 🧵 This week's tips are all about dictionaries. #Python #DailyPythonTip

Python Tip #37 (of 365): Avoid overusing the term "method". 🧵 In Python, the words "function" and "method" are not interchangeable. All methods are functions, but not all functions are methods. #Python #DailyPythonTip

Python Tip #36 (of 365): When accepting any number of objects to a function, consider when to accept an iterable and when to use * instead. 🧵 #Python #DailyPythonTip

Python Tip #37 (of 365): If you're missing function overloading from another programming language, try default argument values as an alternative. 🧵 Default arguments are not a full replacement for function overloading, but they can often be used to reach a similar end. #Python #DailyPythonTip

Python Tip #36 (of 365): Instead of assigning a lambda function to a variable, use a "def" statement. 🧵 Instead of this: square = lambda n: n**2 Write this: def square(n): return n**2 #Python #DailyPythonTip

Python Tip #35 (of 365): When calling "functions", think in terms of "callables". 🧵 Most Python programmers occasionally use the word "function" to describe a class. So when you see the word "function", unless we're talking about a function definiton, think "callable". #Python #DailyPythonTip

New screencast on where we play "the class or function game". This is a game I often play with my students to demonstrate that the word "function" is a bit fuzzy in the #Python world.

Folks, have you been overwhelmed by ~All This~ and wanting a gentle compassionate space to think about agentic coding?? Good news: if you're in SF & have free time tomorrow afternoon you can come hang out with me and @anthrocypher.bsky.social in a popup casual learning event ❤️ luma.com/rdw3dq4h

Python Tip #34 (of 365): Remember that in Python, functions are objects. 🧵 If you need to call a bit of code later, you don't need to make a class with a method... you could just make a function! #Python #DailyPythonTip

Python Tip #33 (of 365): Don't sleep on Python's keyword arguments / named arguments. 🧵 When you have the choice between a positional argument or a keyword argument, choose a keyword argument if it clarifies the argument's purpose. #Python #DailyPythonTip

Python Tip #32 (of 365): When processing potentially large untrusted files, don't iterate over them. 🧵 #Python #DailyPythonTip

Python Tip #31 (of 365): If you need to preserve the original line endings when reading or writing a file, use newline="" when opening your file. 🧵 #Python #DailyPythonTip

Python Tip #30 (of 365): Consider file modes outside of read and write: you may (very occasionally) want a different mode. 🧵 #Python #DailyPythonTip

Python Tip #29 (of 365): When processing small files line-by-line, just read the whole thing into memory. 🧵 Reading files line-by-line with a "for" loop is a good practice for files that could be large, but for small files I would recommend reading the whole file at once. #Python #DailyPythonTip

Python Tip #28 (of 365): Read large files line-by-line by looping over them. 🧵 If you are working with a file that could be very large (such as a log file that could be gigabytes in size), don't read the whole file all at once. #Python #DailyPythonTip

New screencast about how all iteration is the same in Python. In #Python (largely thanks to our embrace of duck typing), looping is looping.

Checking whether iterables are equal in Python: https://trey.io/0frqkp #Python

I just added quiz questions to my introductory Python course, Python Jumpstart... a feature I wish I'd had on day 1! All existing users will now see 64 quiz questions in Jumpstart. In total, Jumpstart includes 60 instructional videos, 64 quizzes, & 48 exercises. It's now VERY hands-on.

Python Tip #27 (of 365): Consider printing to files instead of writing. 🧵 If you're converting objects to strings to write them to a file, I'd use print() instead. And if you're putting newlines in string literals in your write() calls, I'd consider switching to print(). #Python #DailyPythonTip

Often there's a better way to write your code than using break in a loop. Read more 👉 https://trey.io/xtql6h #Python

You should implement dunder methods on your objects, but you shouldn't call dunder methods on other objects. Read more 👉 https://trey.io/p0h32w #Python

Python Tip #26 (of 365): When opening a file, use a "with" block... especially for writing! 🧵 Closing files once you're done with them is a good practice in general. And using a "with" block to open a file will close it automatically when the "with" block exits. #Python #DailyPythonTip

Python Tip #25 (of 365): Don't associate "for" loops with data structures: just think "iterable". 🧵 Python's "for" loops are not for looping over lists, or even for looping over data structures. They're for looping over iterables. #Python #DailyPythonTip

Python Tip #24 (of 365): When you read "iterable" think "I can loop, one time". 🧵 Some iterables, like lists, tuples, and sets, can be looped over as many times as you'd like and you'll always get the same results. But not ALL iterables can be looped over more than once. #Python #DailyPythonTip

This was the first book I read this year and is absolutely going to be one of the best I read all year. If you believe illegal immigration is a cause for concern, please read this. It's quite convincing.

Once again, immigration is not even a problem. Immigrants are not more criminal, they don't cost jobs, they don't harm the economy. There is no reason for any of this. It is hurting ourselves to hurt them.

Python Tip #23 (of 365): To loop over multiple iterables simultaneously, use Python's built-in zip function. 🧵 #Python #DailyPythonTip

Python Tip #22 (of 365): Before using "break" in a loop, consider whether there's a more specialized tool you could use instead. 🧵 #Python #DailyPythonTip

A lot of Python community work happens in the background thanks to folks like Ee who have for years helped make sure that messy (often thankless) work gets done. Big thanks to Ee for all they've done while working for The PSF and volunteering long before that as well. 💜

"I don’t care if you’re vegan, vegetarian, flexitarian, or a meat-lover — it’s your motivation that matters, not your diet." On climate change, animal welfare, the necessity of reducing meat consumption to address both problems, and how massively neglected this problem space is. A great read.

Python Tip #21 (of 365): When you think "I need the reverse of this list", consider the built-in reversed() function before other options. 🧵 #Python #DailyPythonTip

Python Tip #20 (of 365): Don't use "range(len(...))" 🧵 If you find yourself using "range(len(...))" in a loop, always pause to ask "is there a better way to do this?" There usually is. #Python #DailyPythonTip

Boosting this because this is a good offer if you're interested. Philip is someone I'd trust to help me with Mastodon questions.

Unlike f-strings, t-strings don't actually make strings. Read more 👉 https://trey.io/n4mlgb #Python

Python Tip #19 (of 365): Prefer "for" loops over "while" loops. 🧵 Instead of this: n = 1 while n < 10: print(n) n += 1 Prefer this: for n in range(1, 10): print(n) When you're considering a "while" loop, ask whether there's a way to use "for" loop instead. #Python #DailyPythonTip

Python Tip #18 (of 365): Merge iterables using asterisks, like this: "[*first, *second]" 🧵 To merge two iterables, first and second, into third don't do this: third = list(first) + list(second) Do this: third = [*first, *second] Why?... #Python #DailyPythonTip

Python Tip #17 (of 365): Avoid using the "in" operator on lists... especially large lists! 🧵 A containment check (using the "in" operator) on a list requires looping over the list. To repeatedly check whether something is contained in a list, consider using a set instead. #Python #DailyPythonTip

Python Tip #16 (of 365): To pre-fill lists with immutable values, use self-concatenation. 🧵 #Python #DailyPythonTip

This is how free and open access works. There is no way to have a free and open access project and then go “wait, no, not like that”. www.citationneeded.news/free-and-ope...

Meet Joanne, who noticed an influential historical woman was missing on Wikipedia and took action #Wikipedia25

Python Tip #15 (of 365): Don't forget about slicing 🧵 To get all command-line arguments but the first, you COULD do this: import sys arguments = list(sys.argv) arguments.pop(0) But slicing is better for "get all but the first": import sys arguments = sys.argv[1:] #Python #DailyPythonTip

Python Tip #14 (of 365): Use negative indexes. Instead of this: last = items[len(items)-1] Do this: last = items[-1] If you're moving from a language that doesn't have negative indexes, it's easy to forget about them. That's the whole tip! It's a short one today. #Python #DailyPythonTip

Python Tip #13 (of 365): Copy iterables with the list() constructor. 🧵 Need to make a new list out of an existing iterable, without changing anything? Don't use a "for" loop, a comprehension, slicing, or the copy method. Use list()! #Python #DailyPythonTip

@anthropic.com is investing $1.5 million in the PSF, focused on security. These funds will make an enormous impact on the PSF and the security of millions of #Python and @pypi.org#Pythonusers. Please join us in thanking Anthropic for this landmark gift! Read more on our blog:

So when Python opens files, it normalizes all line endings to simply be represented as line feed characters (\n). Read more 👉 https://trey.io/ca0qyn #Python

Python Tip #12 (of 365): Use "[]" to create empty lists instead of calling "list()". 🧵 (This week's tips will all be related to lists) #Python #DailyPythonTip

Python Tip #11 (of 365): Avoid comparing to True and False in Python. 🧵 #Python #DailyPythonTip

Python Tip #10 (of 365): When checking for emptiness (or non-emptiness) in Python, use truthiness. 🧵 Instead of this: if len(items) > 0: ... Or this: if len(items): ... Do this: if items: ... #Python #DailyPythonTip

I made a goal to share one #Python tip every day in 2026. Based on the roll that Reuven's been on, I suspect he has a similar goal! If you've been enjoying my tips, check out his as well! We're definitely going to overlap many common tips, but there's no harm in seeing the same tip twice!

Python Tip #9 (of 365): When checking for None in Python, use identity instead of equality. 🧵 Use "result is None" instead of "result == None". Using identity works because Python's None is a sentinel value, meaning there's exactly one None object in Python. #Python #DailyPythonTip