Seb Fru created ARROW-3866:
------------------------------
Summary: Column metadata is not transferred to tables in pyarrow
Key: ARROW-3866
URL: https://issues.apache.org/jira/browse/ARROW-3866
Project: Apache Arrow
Issue Type: Bug
Components: Python
Reporter: Seb Fru
Hello everyone,
transferring this from Github for Pyarrow. While working with pyarrow I noticed
that field metadata does not get carried foreward when creating a table out of
several columns. Is this intended behaviour or is there a way to add column
metadata later on? The last command in my example does not return anything.
I also could not verify whether this data would be written to parquet later
on, because I could not find a way to add field metadata directly to a table.
{code:java}
>>>import pyarrow as pa
>>>import pyarrow.parquet as pq
>>>arr1 = pa.array([1,2])
>>>arr2 = pa.array([3,4])
>>>field1 = pa.field('field1', pa.int64())
>>>field2 = pa.field('field2', pa.int64())
>>>field1 = field1.add_metadata({'foo1': 'bar1'})
>>>field2 = field2.add_metadata({'foo2': 'bar2'})
>>>field1.metadata {b'foo1': b'bar1'}
>>>field2.metadata {b'foo2': b'bar2'}
>>>col1 = pa.column(field1, arr1)
>>>col2 = pa.column(field2, arr2)
>>>col1.field.metadata {b'foo1': b'bar1'}
>>>tab = pa.Table.from_arrays([col1, col2])
>>>tab pyarrow.Table field1: int64 field2: int64
>>>tab.column(0).field.metadata
{code}
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
