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ENH: groupby.apply for Categorical groupers should preserve categories (like .agg) #10138

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jreback opened this issue May 14, 2015 · 1 comment · Fixed by #10142
Closed

ENH: groupby.apply for Categorical groupers should preserve categories (like .agg) #10138

jreback opened this issue May 14, 2015 · 1 comment · Fixed by #10142
Labels
Categorical Categorical Data Type Enhancement Groupby
Milestone
0.16.2

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@jreback
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jreback commented May 14, 2015

from SO

missing = pd.Categorical(list('aaa'), categories=['a', 'b'])
dense = pd.Categorical(list('abc'))
values = np.arange(len(dense))
df = pd.DataFrame({'missing': missing, 'dense': dense, 'values': values})

grouped = df.groupby(['missing', 'dense'])

# does reindex output for missing categories
grouped.mean()
grouped.agg(np.mean)

# does not reindex the output for the missing categories
grouped.apply(lambda chunk: np.mean(chunk))

So the _wrap_applied_output need a call to _reindex_output as a post-processing step.
@jreback jreback added this to the Next Major Release milestone May 14, 2015
@mortada
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mortada commented May 15, 2015

seems straight forward, I'll submit a PR for this

mortada added a commit to mortada/pandas that referenced this issue May 15, 2015
@mortada
ENH: groupby.apply for Categorical should preserve categories (closes p…
d8b49d5 
…andas-dev#10138)
@mortada mortada mentioned this issue May 15, 2015
Merged
@jreback jreback modified the milestones: 0.17.0, Next Major Release May 16, 2015
mortada added a commit to mortada/pandas that referenced this issue May 16, 2015
@mortada
ENH: groupby.apply for Categorical should preserve categories (closes p…
bef6932 
…andas-dev#10138)
mortada added a commit to mortada/pandas that referenced this issue May 16, 2015
@mortada
ENH: groupby.apply for Categorical should preserve categories (closes p…
aeef3c2 
…andas-dev#10138)
mortada added a commit to mortada/pandas that referenced this issue May 21, 2015
@mortada
ENH: groupby.apply for Categorical should preserve categories (closes p…
659bbec 
…andas-dev#10138)
mortada added a commit to mortada/pandas that referenced this issue Jun 2, 2015
@mortada
ENH: groupby.apply for Categorical should preserve categories (closes p…
eb33cf2 
…andas-dev#10138)
@jreback jreback modified the milestones: 0.16.2, 0.17.0 Jun 2, 2015
mortada added a commit to mortada/pandas that referenced this issue Jun 2, 2015
@mortada
ENH: groupby.apply for Categorical should preserve categories (closes p…
c8bf1c4 
…andas-dev#10138)
cgevans added a commit to cgevans/pandas that referenced this issue Jun 5, 2015
@cgevans
Merge https://github.com/pydata/pandas into fastsplit
db330d4 
* https://github.com/pydata/pandas: (26 commits)
  disable some deps on 3.2 build
  Fix meantim typo
  DOC: use current ipython in doc build
  PERF: write basic datetimes faster pandas-dev#10271
  TST: fix for bottleneck >= 1.0 nansum behavior, xref pandas-dev#9422
  add numba example to enhancingperf.rst
  BUG: SparseSeries constructor ignores input data name
  BUG: Raise TypeError only if key DataFrame is not empty pandas-dev#10126
  ENH: groupby.apply for Categorical should preserve categories (closes pandas-dev#10138)
  DOC: add in whatsnew/0.17.0.txt
  DOC: move whatsnew from 0.17.0 -> 0.16.2
  BUG:  Holiday(..) with both offset and observance raises NotImplementedError pandas-dev#10217
  BUG: Index.union cannot handle array-likes
  BUG: SparseSeries.abs() resets name
  BUG: Series arithmetic methods incorrectly hold name
  ENH: Don't infer WOM-5MON if we don't support it (pandas-dev#9425)
  BUG: Series.align resets name when fill_value is specified
  BUG: GroupBy.get_group raises ValueError when group key contains NaT
  Close mysql connection in TestXMySQL to prevent tests freezing
  BUG: plot doesnt default to matplotlib axes.grid setting (pandas-dev#9792)
  ...
yarikoptic added a commit to neurodebian/pandas that referenced this issue Jul 2, 2015
@yarikoptic
Merge commit 'v0.16.1-97-gbc7d48f' into debian
9a51574 
* commit 'v0.16.1-97-gbc7d48f': (56 commits)
  disable some deps on 3.2 build
  Fix meantim typo
  DOC: use current ipython in doc build
  PERF: write basic datetimes faster pandas-dev#10271
  TST: fix for bottleneck >= 1.0 nansum behavior, xref pandas-dev#9422
  add numba example to enhancingperf.rst
  BUG: SparseSeries constructor ignores input data name
  BUG: Raise TypeError only if key DataFrame is not empty pandas-dev#10126
  ENH: groupby.apply for Categorical should preserve categories (closes pandas-dev#10138)
  DOC: add in whatsnew/0.17.0.txt
  DOC: move whatsnew from 0.17.0 -> 0.16.2
  BUG:  Holiday(..) with both offset and observance raises NotImplementedError pandas-dev#10217
  BUG: Index.union cannot handle array-likes
  BUG: SparseSeries.abs() resets name
  BUG: Series arithmetic methods incorrectly hold name
  ENH: Don't infer WOM-5MON if we don't support it (pandas-dev#9425)
  BUG: Series.align resets name when fill_value is specified
  BUG: GroupBy.get_group raises ValueError when group key contains NaT
  Close mysql connection in TestXMySQL to prevent tests freezing
  BUG: plot doesnt default to matplotlib axes.grid setting (pandas-dev#9792)
  ...
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Categorical Categorical Data Type Enhancement Groupby
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ENH: groupby.apply for Categorical should preserve categories (closes… mortada/pandas
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