Joram Mutenge
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jorammutenge.com
Joram Mutenge
@jorammutenge.com
My data consulting company
https://www.conterval.com/
Blogging is like a cheatsheet for your mind.

Whenever you have a conversation with someone on a topic you've written about, you are guaranteed of offering an intelligent contribution.
August 16, 2025 at 12:20 PM
Data analysis is just rearranging numbers, if you distill it to its core.
July 30, 2025 at 1:37 PM
Full article www.conterval.com/blog/copy-pa...
Enough said.
July 16, 2025 at 11:04 PM
The masterpiece is finally published!

One reader said I invented a who new book genre: "narrativized data analysis"

Click "Read sample" and read a few pages here www.amazon.com/dp/B0FHFWZFT9/
EMAILS FROM A BIG DATA ENTREPRENEUR TO HIS SON
EMAILS FROM A BIG DATA ENTREPRENEUR TO HIS SON: 9798292273066: Computer Science Books @ Amazon.com
www.amazon.com
July 15, 2025 at 10:49 PM
Filtering for multiple items is easy in @pola.rs
Full article www.conterval.com/blog/filter-...
July 15, 2025 at 12:06 AM
Yes, aggregations can also be done on text data in @pola.rs

www.conterval.com/blog/aggrega...
July 12, 2025 at 3:58 PM
"History is too often not what happened, but what was recorded. A lie set down on paper with wet ink becomes a truth when dry."
July 7, 2025 at 5:05 PM
So you want to learn how to #code?
Full article:

www.conterval.com/blog/
July 5, 2025 at 10:29 AM
Dates are weired. E.g American dates begin with month.

@pola.rs makes it easy to change the way your dates look, depending on the audience.

Here's short and long text date formats. You can do more!

This is the final #100DaysOfPolars post.

Find all the posts here
www.conterval.com/blog/#catego...
June 30, 2025 at 6:51 PM
JSON data can be nested on multiple levels. But @pola.rs has a way to convert it to tabular format based on the level of your choosing.

Best for dealing with API data or web requests in JSON.

Even more ways to use Polars in the course www.udemy.com/course/analy...

#100DaysOfPolars
#data
June 29, 2025 at 12:35 PM
You have a table of passwords and (for whatever reason) you want to count the number of digits in each password.

Here's how to do it with @pola.rs

Even more ways to use Polars in the course www.udemy.com/course/analy...

#100DaysOfPolars
#datasky
June 28, 2025 at 4:09 PM
He is a nice trick to demonstrate how versatile @pola.rs is.

I have parts of a phone number and want to join them into a complete phone number.

More tricks in the Polars course www.udemy.com/course/analy...

#100DaysOfPolars
#datasky
June 27, 2025 at 1:09 PM
What if you wanted to round time the way round decimal numbers? Well, sort of

Here, I use @pola.rs to scan a 10 minute interval and make the value in between same as the lower bound. So minutes between 0 and 10 become 0, minutes between 10 and 20 become 10 etc.

#100DaysOfPolars
#datasky
June 26, 2025 at 1:58 PM
Maybe they're keeping it a secret. Full article:

www.conterval.com/blog/ibis-fo...

@voltrondata.bsky.social
June 26, 2025 at 12:40 PM
In @pola.rs, it's very easy to make the first letter of each word a capital letter.

Here, I properly punctuate the book titles of some of my favorite authors.

#100DaysOfPolars
#datasky
June 25, 2025 at 6:15 PM
June 24, 2025 at 10:31 PM
When you have timeseries data, @pola.rs has a special type of grouping that lets you be a lot more granular in your grouping.

Here, we see the total power usage every 5 hours and 30 minutes. Now that's granular!

#100DaysOfPolars
#datasky
June 24, 2025 at 1:40 PM
June 23, 2025 at 11:25 PM
When you change the timezone on your date column, the time also changes. What if you want to change the timezone but maintain the time?

Here's how to do it in @pola.rs

#100DaysOfPolars
#data
June 23, 2025 at 3:16 PM
Data analysis involves neglecting certain rows and focusing on specific rows of data.

Here we use @pola.rs to neglect all rows and focus on one row with the maximum grade.

Even more ways to use Polars in this course www.udemy.com/course/analy...

#100DaysOfPolars
#datasky
June 22, 2025 at 12:25 PM
You have a large Parquet dataset. You want to find out what columns it has and the data types of those columns—without reading the entire dataset.

@pola.rs can help you do just that!

Even more way to use Polars in this course www.udemy.com/course/analy...

#100DaysOfPolars
#datasky
June 21, 2025 at 7:24 PM
June 20, 2025 at 10:42 PM
You are querying a historical database with dates, and you want to create another column of centuries for those dates.

@pola.rs makes it super easy to do this.

Look there's a Polars course www.udemy.com/course/analy...

#100DaysOfPolars
#datasky
June 20, 2025 at 10:31 AM
June 20, 2025 at 12:24 AM
Sometimes you may have a column identified as a string when it's supposed to be a decimal.

Here, I use @pola.rs to convert the data type to decimal.

This is different from float type. You can see in the type that the max number of digits after the decimal point is 2.

#100DaysOfPolars
#datasky
June 19, 2025 at 12:25 PM