Effective Pandas I Matt Harrison I PyData Salt Lake City Meetup

[@MartyAckerman310]

I'm not exaggerating when I say this video changed my life. I went from a guy who did everything upstream in SQL and grudgingly used Pandas to a guy who uses Pandas for everything. The approach Matt demonstrates also translates generally to PySpark. I'm now considered the go-to guy for Pandas and PySpark code in my department. There's so much bad code around, often written by people with advanced degrees and MATLAB experience it seems. I could make a full time job out of cleaning up bad code. Dot chain FTW!

[@mattharrison721]

Thanks! Glad to help.

[@amilkyboi]

Heh, MATLAB and bad coding practices - the two are never far from one another it seems.

[@flipside5482]

This man is a living data legend. Mass respect.

[@bendirval3612]

This was a ridiculously useful video. I feel like I've watched a lot of python videos, but I think this might be the most practically useful for people who are not brand new to pandas--who use it all the time.

[@ninhluong5004]

This is easily the best pandas guide I have ever watched so far.

[@mattharrison721]

Thank you!

[@DavidDobr]

90 minutes of pure gold. Thanks Matt!

[@mattharrison721]

Thanks David. 👍🙏 Make sure you check out my book, Effective Pandas, if you appreciated this.

[@scottlucas232]

AGREE COMPLETELY ! FANTASTIC PRESENTATION ! Learned more here than in past two years

[@AkashRana1111]

This is gold! Matt did an amazing job showing best practices when using pandas and a lot of intuition about how pandas function run under the hood.

[@nickhodgskin]

Really interesting talk, was doubtful about chaining at first but you have converted me :) . A very very informative talk, thanks

[@mattharrison721]

Thanks for coming around Nick. 😉 Hope you find these techniques useful to you.

[@erginceyhan]

Great presentation. As others said pure gold. If there is button called pure gold I would have clicked it. A simple like is not enough. It also changed my view of code organization. Thanks for sharing.

[@johannes-euquerofalaralema4374]

By far the best pandas video I have ever seen

[@NearLWatson]

I was looking how to speed up my pandas operations since I read Python itself is faster than R and pandas should be faster than python, i am happy i came here. Excellent tips that I am going to experiment and hopefully achieve a quicker output time. Excellent session nevertheless.

[@annagora6409]

Matt, big thank you for chaining idea!

[@rephechaun]

This is mind blowing... Thank you very much!

[@gregorywpower]

I can’t wait for you to give another talk on polars!

[@whkoh7619]

Thanks Matt, this was an incredible presentation. Came here from the Real Python podcast, just bought the book too!

[@mattharrison721]

Thanks for your support

[@aoihana1042]

This tutorial had so many gems! Thanks Matt

[@bullbranch]

Excellent Pandas best practices video. I was already a big user of chaining but for some reason hadn't used append much. This is a cleaner way to do things and I will be using it. My next notebook is going to be much easier to maintain and much easier to build. Thanks Matt!

[@mattharrison721]

Awesome. Thanks

[@elidrissii]

Here from your HN comment. Super informative.

[@hazemmosaad3440]

Really interesting and informative talk. Thanks

[@FRANKWHITE1996]

Thanks for sharing ❤

[@Davidkiania]

I really love this session and it’s completely changed the way I process data going forward. Thanks a lot !

[@santchev1326]

Really interesting, many thanks to Matt and Pydata :)

[@grumpy_techo]

Thanks for you 'rant' Matt - have your recent books and still realised something that I should be doing with my data. 👌

[@mattharrison721]

Thanks Tyrone! Good luck with your Pandas. 😉🐼

[@samplaying4keeps]

Thank you for this! This is super helpful. I learned so much!

[@firefoxmetzger9063]

1:18:00 For the specific question being asked (find duplicates in a primary key) there is a much simpler solution than what Matt Harrison suggested: df.duplicated("primary_key", keep=False). It will select all rows with non-unique values in the "primary_key" column, i.e., all the rows that are duplicated. Matt solves the more general problem of "find all rows for which the element in primary_key occurs at least N times". A more concise (though perhaps less readable) solution to this would be something like (df [df.primary_key.value_counts()[df.primary_key].reset_index().primary_key > N] )

[@kernel2006]

An alternative to your approach is to use .transform() with .groupby(), to act effectively like a SQL window function that counts the primary keys, but whose result is the same length as the original data (rather than being collapsed due to aggregation). Something like: num_dups = df.groupby('key')['key'].transform('size') # has same index as df df.loc[num_dups > N]

[@jongcheulkim7284]

Thank you

[@dragangolic6515]

Great video, I need this data set. Where can I find it?

[@ioannisnikolaospappas6703]

Thanks for the wonderful pandas insights matt and pydata!

[@antecavlina8897]

just a tip: at 48:30 when commenting line by line upwards you could point with mouse at desired line, then press (i think) ALT and keep pressed, pointer might switch to a thin lined cross, then drag with mouse pointer up or down the lines and then insert # its like doing block comment... still looking for a way to do that without mouse, but not sure to use sth like vim extension, if there is one...

[@mischaminnee]

Awesome!

[@abimaeldominguez4126]

I have a problem with aggregations, sometimes if you aggregate two columns and one column has a cell with a NaN .groupby will ignore it, I know you can keep those NaNs, but I would like to see a use case when is good idea to keep NaNs while using a .groupby and when is not a good idea.

[@tariqaziz1795]

Sir the apply method gave me error such as unhashable series. How to fix that?

[@pmiron]

Can someone identify the font he uses in Jupyterlab ? :D

[@JimmieChoi93]

'Lato' I guess

[@pmiron]

@@JimmieChoi93 I just tried and I don't think it is Lato.

[@JimmieChoi93]

@@pmiron damn. Here's an idea, screenshot it to ChatGPT and ask

[@pmiron]

@@JimmieChoi93 haha I actually did try with some screenshots. It recognizes that is a notebook and a monospace font but then suggest it might be the default JupyterLab font or Consolas, Menlo, etc. Also tried WhatTheFont and FontSquirrel with no luck.

[@joecookieee]

ty for the video matt this is awesome can you explain how u got those numbers @ 57:30 -- 6_220 / 125 Thank you!

[@walkingintopeople]

235.215 is a ratio between mpg and l/100km. It's a constant the presenter looked up on a search engine ahead of time