June 2017
Beginner to intermediate
446 pages
9h 23m
English
Content preview from Learning pandas - Second Edition
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Filling missing values with the mean of the group
A common transformation in statistical analysis with grouped data is to replace missing data within each group with the mean of the non-NaN values in the group. To demonstrate this, the following code creates a DataFrame with a Label column with two values (A and B) and a Values column containing a series of integers, but with one value replaced with NaN. The data is then grouped by the Label column:
The mean of each group can be calculated using .mean():
Now suppose that we need the B group ...
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.