#66 Pandas (Part 43): GroupBy - 4: Transform in Python | Tutorial

The video discusses GroupBy with Transform in Pandas in Python.

Timeline
(Python 3.7)

00:00 - Welcome
00:13 - Outline of video
00:33 - Open Jupyter notebook
00:40 - Data
01:05 - GroupBy: Create a GroupBy object
02:00 - GroupBy: .mean()
02:23 - GroupBy: Transform: Explanation
03:23 - GroupBy: Transform vs. Apply
04:53 - Create missing values i.e. NaN's in a DataFrame column
05:32 - Set a DataFrame column to Index
05:59 - GroupBy: Create a GroupBy object
06:18 - GroupBy: Transform: .fillna()
06:53 - ----------- CORRECTION -------------: I meant to say "get mean of grade 'A' and put that where there is NaN for grade 'A'". I incorrectly pointed at NaN for grade 'C' instead.
07:20 - GroupBy: Transform: .mean()
07:44 - GroupBy: Transform: Compare .mean() values with and without .fillna()
08:45 - Check for NaN's in a DataFrame: .count()
09:18 - GroupBy: Directly calculate: .mean()
10:20 - Ending notes