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Bryan Cutler commented on ARROW-2101: ------------------------------------- I'm not exactly sure what the right behavior for this is. If you are just staying in a Python 2 env, then it makes sense that {{str}} would correspond to a binary type column and it doesn't cause a problem going to/from Pandas. In PySpark, we are sending Arrow data to Java and it seems like specifying {{pa.string()}} should lead to a string column in Java (a VarCharVector). Currently, we do a check and "decode('utf-8')" before calling {{from_pandas}} which works fine, but I thought maybe that pyarrow should perform a conversion to UTF-8 automatically if the user specifies the type. However, it's also possible that casting to UTF-8 wouldn't be wanted, e.g. if you are only in a Python 2 env and don't mind treating it as a binary column. I guess to sum this issue up, is {{pa.string()}} meant to correspond to an Arrow UTF-8 type or is it special in this case as it depends on if your {{str}} came from Python 2 or 3? cc [~wesmckinn] [~xhochy] [~pitrou] for thoughts > [Python] from_pandas reads 'str' type as binary Arrow data with Python 2 > ------------------------------------------------------------------------ > > Key: ARROW-2101 > URL: https://issues.apache.org/jira/browse/ARROW-2101 > Project: Apache Arrow > Issue Type: Bug > Components: Python > Affects Versions: 0.8.0 > Reporter: Bryan Cutler > Priority: Major > > Using Python 2, converting Pandas with 'str' data to Arrow results in Arrow > data of binary type, even if the user supplies type information. conversion > of 'unicode' type works to create Arrow data of string types. For example > {code} > In [25]: pa.Array.from_pandas(pd.Series(['a'])).type > Out[25]: DataType(binary) > In [26]: pa.Array.from_pandas(pd.Series(['a']), type=pa.string()).type > Out[26]: DataType(binary) > In [27]: pa.Array.from_pandas(pd.Series([u'a'])).type > Out[27]: DataType(string) > {code} -- This message was sent by Atlassian JIRA (v7.6.3#76005)