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https://issues.apache.org/jira/browse/ARROW-1644?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16192314#comment-16192314
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Wes McKinney commented on ARROW-1644:
-------------------------------------
At the moment we do not have mixed-nesting reading and writing implemented. If
the nesting levels are all repeated (lists) or all groups (structs) vs. a mix
(structs and lists/repeated fields) then we can read and write them. I recently
wrote an important patch to help with this (PARQUET-1100
https://github.com/apache/parquet-cpp/commit/4b09ac703bc75fee72f94bed8ecfe571096b04c1),
but we could really use some help with the encoding and decoding of nested
data. I will eventually get to it if no one else does but that could be anytime
from 1 month from now to 6 months from now given how many other projects I have
before me.
> Parquet with nested structs can not be loaded in pyarrow in Oct 2017 nightly
> build
> ----------------------------------------------------------------------------------
>
> Key: ARROW-1644
> URL: https://issues.apache.org/jira/browse/ARROW-1644
> Project: Apache Arrow
> Issue Type: Bug
> Components: Python
> Affects Versions: 0.8.0
> Reporter: DB Tsai
>
> We have many nested parquet files generated from Apache Spark for ranking
> problems, and we would like to load them in python for other programs to
> consume.
> The schema looks like
> {code:java}
> root
> |-- profile_id: long (nullable = true)
> |-- country_iso_code: string (nullable = true)
> |-- items: array (nullable = false)
> | |-- element: struct (containsNull = false)
> | | |-- show_title_id: integer (nullable = true)
> | | |-- duration: double (nullable = true)
> {code}
> And when I tried to load it with nightly build pyarrow on Oct 4, 2017, I got
> the following error.
> {code:python}
> Python 3.6.2 |Anaconda, Inc.| (default, Sep 30 2017, 18:42:57)
> [GCC 7.2.0] on linux
> Type "help", "copyright", "credits" or "license" for more information.
> >>> import numpy as np
> >>> import pandas as pd
> >>> import pyarrow as pa
> >>> import pyarrow.parquet as pq
> >>> table2 = pq.read_table('part-00000')
> Traceback (most recent call last):
> File "<stdin>", line 1, in <module>
> File "/home/dbt/miniconda3/lib/python3.6/site-packages/pyarrow/parquet.py",
> line 823, in read_table
> use_pandas_metadata=use_pandas_metadata)
> File "/home/dbt/miniconda3/lib/python3.6/site-packages/pyarrow/parquet.py",
> line 119, in read
> nthreads=nthreads)
> File "_parquet.pyx", line 466, in pyarrow._parquet.ParquetReader.read_all
> File "error.pxi", line 85, in pyarrow.lib.check_status
> pyarrow.lib.ArrowNotImplementedError: lists with structs are not supported.
> {code}
> I somehow get the impression that after
> https://issues.apache.org/jira/browse/PARQUET-911 is merged, we should be
> able to load the nested parquet in pyarrow.
> Any insight about this?
> Thanks.
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