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https://issues.apache.org/jira/browse/ARROW-2787?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Alex Hagerman updated ARROW-2787:
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    Summary: [Python] Memory Issue passing table from python to c++ via cython  
(was: Memory Issue passing table from python to c++ via cython)

> [Python] Memory Issue passing table from python to c++ via cython
> -----------------------------------------------------------------
>
>                 Key: ARROW-2787
>                 URL: https://issues.apache.org/jira/browse/ARROW-2787
>             Project: Apache Arrow
>          Issue Type: Bug
>          Components: Integration, Python
>    Affects Versions: 0.9.0
>         Environment: clang6
>            Reporter: Joseph Toth
>            Priority: Major
>              Labels: cython
>
> I wanted to create a simple example of reading a table in Python and pass it 
> to C+, but I'm doing something wrong or there is a memory issue. When the 
> table gets to C+ and I print out column names it also prints out a lot of 
> junk and what looks like pydocs. Let me know if you need any more info. 
> Thanks!
>  
> *demo.py*
> import numpy
> from psy.automl import cyth
> import pandas as pd
> from absl import app
> def main(argv):
>   sup = pd.DataFrame({
>   'int': [1, 2],
>   'str': ['a', 'b']
>   })
>   table = pa.Table.from_pandas(sup)
>   cyth.c_t(table)
> *cyth.pyx*
> import pandas as pd
> import pyarrow as pa
> from pyarrow.lib cimport *
> cdef extern from "cyth.h" namespace "psy":
>  void t(shared_ptr[CTable])
> def c_t(obj):
>  # These print work
>  # for i in range(obj.num_columns):
>  # print(obj.column(i).name
>   cdef shared_ptr[CTable] tbl = pyarrow_unwrap_table(obj)
>   t(tbl)
>  *cyth.h*
> #include <iostream>
> #include <string>
> #include "arrow/api.h"
> #include "arrow/python/api.h"
> #include "Python.h"
> namespace psy {
> void t(std::shared_ptr<arrow::Table> pytable) {
> // This works
>   std::cout << "NUM" << pytable->num_columns();
> // This prints a lot of garbage
>   for(int i = 0; i < pytable->num_columns(); i++) {
>   std::cout << pytable->column(i)->name();
>   }
>  }
>  



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