[
https://issues.apache.org/jira/browse/ARROW-1743?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16248784#comment-16248784
]
ASF GitHub Bot commented on ARROW-1743:
---------------------------------------
Licht-T commented on issue #1260: ARROW-1743: [Python] Avoid non-array
writeable-flag check
URL: https://github.com/apache/arrow/pull/1260#issuecomment-343713108
@wesm Seems no problem.
```bash
[python] python
13:39:23 ☁
fix-non-array-writable-check ☀
Python 2.7.10 (default, Oct 23 2015, 19:19:21)
[GCC 4.2.1 Compatible Apple LLVM 7.0.0 (clang-700.0.59.5)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import pandas as pd
>>> import pyarrow as pa
>>>
>>>
>>> pd.__version__
u'0.19.2'
>>>
>>> df = pd.DataFrame({'a': [1, 2, 3], 'b': [1, 2, 3]})
>>> df['a'] = df.a.astype('category')
>>> df = df.set_index('a')
>>>
>>> tbl = pa.Table.from_pandas(df)
>>> df_new = tbl.to_pandas()
>>>
>>> pd.factorize(df_new['b'])
(array([0, 1, 2]), Int64Index([1, 2, 3], dtype='int64'))
```
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> [Python] Table to_pandas fails when index contains categorical column
> ---------------------------------------------------------------------
>
> Key: ARROW-1743
> URL: https://issues.apache.org/jira/browse/ARROW-1743
> Project: Apache Arrow
> Issue Type: Bug
> Components: Python
> Affects Versions: 0.7.1
> Reporter: Brian Pendleton
> Assignee: Licht Takeuchi
> Labels: pull-request-available
> Fix For: 0.8.0
>
>
> Categorical columns in the index of a dataframe are causing a roundtrip
> failure.
> {code}
> >>> df = pd.DataFrame({'a': [1, 2, 3], 'b': [1, 2, 3]})
> >>> df['a'] = df.a.astype('category')
> >>> df = df.set_index('a')
> >>> tbl = pa.Table.from_pandas(df)
> >>> tbl.to_pandas()
> Traceback (most recent call last):
> File "<stdin>", line 1, in <module>
> File "table.pxi", line 881, in pyarrow.lib.Table.to_pandas
> File
> "C:\Users\bpendlet\Miniconda3\envs\panpy3\lib\site-packages\pyarrow\pandas_compat.py",
> line 303, in table_to_blockmanager
> if not values.flags.writeable:
> AttributeError: 'Categorical' object has no attribute 'flags'
> {code}
> Works as expected when you don't change have the categorical:
> {code}
> >>> df = pd.DataFrame({'a': [1, 2, 3], 'b': [1, 2, 3]})
> >>> df = df.set_index('a')
> >>> tbl = pa.Table.from_pandas(df)
> >>> tbl.to_pandas()
> b
> a
> 1 1
> 2 2
> 3 3
> {code}
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