Doc: Added warning to treat group chunks as immutable when using apply #19114
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pdpark
commented
Jan 7, 2018
pdpark
commented
- closes issue DOC: clarify dangers of fast apply in GroupBy apply docs #14180
added 4 commits
December 27, 2017 00:14
…utomatic-exclusion-of-nuisance-columns section
…ly" section of groupby.rst Resolves: pandas-dev#14180
jreback
requested changes
Jan 7, 2018
| @@ -332,3 +332,97 @@ using something similar to the following: | |||
| See `the NumPy documentation on byte order | |||
| <https://docs.scipy.org/doc/numpy/user/basics.byteswapping.html>`__ for more | |||
| details. | |||
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| Alternative to storing lists in Pandas DataFrame Cells | |||
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| Alternative to storing lists in Pandas DataFrame Cells | ||
| ------------------------------------------------------ | ||
| Storing nested lists/arrays inside a pandas object should be avoided for performance and memory use reasons. Instead they should be "exploded" into a flat DataFrame structure. |
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use double backticks around DataFrame
| .. ipython:: python | ||
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| from collections import OrderedDict | ||
| df = (pd.DataFrame(OrderedDict([('name', ['A.J. Price']*3), |
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use dict contruction directly, if you want column ordering then pass columns
| )) | ||
| df | ||
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| nn = [['Zach LaVine', 'Jeremy Lin', 'Nate Robinson', 'Isaia']]*3 |
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call this something more apparent
| nn = [['Zach LaVine', 'Jeremy Lin', 'Nate Robinson', 'Isaia']]*3 | ||
| nn | ||
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| # Step 1: Create an index with the "parent" columns to be included in the final Dataframe |
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you can use sphinx to number these
| @@ -955,6 +959,42 @@ will be (silently) dropped. Thus, this does not pose any problems: | |||
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| df.groupby('A').std() | |||
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| .. note:: | |||
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Yes, I should have made this a separate branch on my fork and separate pull request.
I will make the updates per your notes above.
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I created a clean pull request for this fix: #19215
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superseded by #19175 |
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