@lernerpython.com.bsky.social
Helping you become more confident with Python and Pandas since 1995. • Courses: LernerPython.com • Newsletters: BetterDevelopersWeekly.com • BambooWeekly.com • Books: PythonWorkout.com • PandasWorkout.com • Videos: YouTube.com/reuvenlerner
Last week's US jobs report reduced previous estimates, leading to the firing of the head statistician.
Today's Bamboo Weekly examines the BLS data, calculating these changes ourselves with #Python #Pandas.
Improve your data skills every Wednesday: bambooweekly.com
Do you usually separate groups of digits with commas? Do that in #Python, and you'll have trouble.
In my latest video, I show you how to separate digits in Python, and then how to display numbers separated by commas, too.
Check it out: youtu.be/hhgg9SFyQZs?...
IIBA Chicagoland Chapter
Showcasing the Powers of Jupyter -
@lernerpython.com Reuven Lerner
Join us on Zoom this Wed!
Aug 6, 6:00-7:30pm CT
Cost: Free
chicago.iiba.org/.../showcasi...
#Python #Jupyter #Pandas #DataFormats #Export #Import #BusinessAnalysis
Tom Lehrer passed away this week, so the latest Bamboo Weekly is about analyzing his lyrics with #Python #Pandas:
• Create a data frame from text files
• Using .str methods
• Extract text with regex
Improve your data-analysis skills each Wednesday: bambooweekly.com
Oh, and I had *completely* forgotten that we met when you took my class with Cisco! I figured that we had met at PyCon US a number of years ago...
30.07.2025 04:46 — 👍 1 🔁 0 💬 0 📌 0
Yeah, I wouldn't phrase it this way. I think you're somewhat confusing the idea of a constant (where a variable's reference to a value is fixed and unchangeable) and immutable (where a value cannot change).
Maybe this will help: www.youtube.com/watch?v=XPrZ...
True -- we talk about mutable vs. immutable as if they were strictly defined categories, and that everything falls into one or the other. But aside from some builtin data structures, nothing in Python is truly immutable. We can create almost-immutable values, but it's never 100%.
30.07.2025 04:40 — 👍 1 🔁 0 💬 0 📌 0Fair enough!
That said, I always love showing this to people:
t = ([10, 20, 30], [40, 50, 60])
t += [35]
which has more to do with magic methods than with immutability, but I'll do anything to shock my students. :-)
No! You can think of the tuple as containing a fixed number of reference (pointers, more or less) to another object. The references cannot change -- you can't add new ones, remove existing ones, or modify existing ones -- but the objects to which they refer *can* change.
29.07.2025 18:40 — 👍 0 🔁 0 💬 1 📌 0
#Python people talk a lot about "mutable" and "immutable" data.
What does that mean, though?
In my latest video, I break it down, showing you what it means for a data structure (e.g., a list or dict) to be mutable.
youtu.be/qfQBMq4IH1s?...
Ever use the x=y=z syntax in #Python, assigning multiple variables at the same time?
Ever discover it didn't quite work right?
In my latest video, I show you what's happening behind the scenes, and where this syntax can bite you: youtu.be/rm_T1x3VnMU?...
I'm now an old hand at #Python conferences, and feel very comfortable there. But for many, it can be overwhelming and daunting.
Here are some tips for anyone attending a conference for the first time, who wants to get the most out of it: lerner.co.il/2025/07/27/h...
It's summer in much of the world, and this summer is *hot*!
In the latest Bamboo Weekly, I pose six questions based on European climate data. But we also explore xarray, PyArrow, pivot tables, plotting, and memory optimization.
Level up your #Python #Pandas every Wednesday: bambooweekly.com !
Using #Python #Pandas? I've been teaching it for many years, and I've seen lots of people make the same mistakes.
In my latest video, I review (and explain) those mistakes, and how to correct them: www.youtube.com/watch?v=ctpl...
Confused by #Python comprehensions? You're not alone! Lots of people find the syntax a bit mystifying.
In this video, I break down what comprehensions do, how to use them, and how to write them so that you can better understand what's going on: www.youtube.com/watch?v=EqAE...
I had a great time presenting, "What does = do?" at @europython.eu earlier today in Prague.
I've uploaded the slides, if you want to take a look:
speakerdeck.com/reuven/what-...
Delightfully emcouraging keynote from @savannah.dev at @europython.eu about how everyone can, and should, contribute to Python... And that everyone does something different, in their own way, which is a good thing.
A great way to start the conference!
Some #Python #Pandas calculations seem like they need a "for" loop:
• By how much (amount or %) does each row differ from the previous one?
• Aggregate over every group of 5 consecutive rows
You don't need a loop. You need a Pandas windowing methods.
Learn more: www.youtube.com/watch?v=BzB0...
Trying to get integer input from a user in #Python? You can, of course, run int() on the result from input(). But what if the user enters non-numeric data?
In my latest video, I show you two ways to handle this, and why exception handling is the more "Pythonic": www.youtube.com/watch?v=nW-7...
How many Americans bought electric vehicles (EVs) in the last decade?
In the latest Bamboo Weekly, I pose six problems on this topic, using data from the Department of Transportation.
Level up your #Python #Pandas skills every Wednesday: bambooweekly.com
Q: If we can retrieve from a #Python #Pandas datetime column, then what's the advantage of a time series?
A: You can do three things that would otherwise be annoying or impossible:
1. Wildcard date retrieval
2. Date slices
3. Resampling
Take a look: youtu.be/M4qhlzzrCXg
Reading an Excel file into a Pandas data frame isn't hard.
But what if you want 2 columns to be a multi-index... and one is unnamed?
In my latest video, I show you how to create a multi-index in such cases. *PLUS* we talk about assign, transpose, and pipe.
Check it out: youtu.be/wf_nbP-S5rk?...
A lot of #Python developers think that "with" is about opening files. And it's certainly used there! But it's much more than that.
In this video, I explain what "with" does, the context-manager protocol, and how to make your own objects behave inside of a "with" block:
youtu.be/i3iqByWM7icl...
Want to replace your #Python #Pandas data frame's default index with one of its columns? Use set_index, of course.
But it's faster and easier to pass index_col to read_csv, letting you set indexes, multi-indexes, and time-series indexes.
Watch and learn: youtu.be/kzUyeMcMQLw?...
You've been told not to use "for" loops in #Python #Pandas. Or to use "apply". So you use ".str" instead.
But sometimes "str" is slower than "apply". How can this be?
In my latest video, I explain why — and demonstrate PyArrow strings, which run 20x faster.
Watch here: youtu.be/Ovz8F464uo0?...
I wonder if individuals and small teams will see a big boost, but large teams won't - because the bottleneck on a team is often communication.
Of course, if an AI tool lets you replace a big team with a small one, then your overall deployment rate won't change, but per person LOC will.
I've been in business for 30 years. I can't imagine sending such a letter to any of my colleagues, suppliers, clients, employees... anyone at all, actually, and expect to be taken seriously.
And yet... that's the current reality.
Have you ever merged two #Python #Pandas data frames together, only to find that one column has a _x suffix, and another has a _y suffix?
Wonder where this comes from, and how you can change it?
I explain it all in my latest video: youtu.be/1hYIC4sT5dk?...
Want to know if the US dollar rose or fell each year? That's easy.
But if you want to know whether it rose or fell during the *first half* of each year? That's trickier!
In my latest video, I walk you through how to solve such a problem using #Python #Pandas: youtu.be/KMn16l7RoM4?...
Want to get the log of a file you deleted in Git?
Want to restore a file you deleted in a previous commit?
In my latest video, I show you how deleting (and un-deleting) work in Git, and why: youtu.be/oT4__qrXYy8?
