April 2015
Beginner to intermediate
504 pages
8h 36m
English
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Working with missing data
Data is "missing" in pandas when it has a value of NaN (also seen as np.nan—the form from NumPy). The NaN value represents that in a particular Series that there is not a value specified for the particular index label.
In pandas, there are a number of reasons why a value can be NaN:
- A join of two sets of data does not have matched values
- Data that you retrieved from an external source is incomplete
- The
NaNvalue is not known at a given point in time and will be filled in later - There is a data collection error retrieving a value, but the event must still be recorded in the index
- Reindexing of data has resulted in an index that does not have a value
- The shape of data has changed and there are now additional rows or columns, which ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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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.