[
https://issues.apache.org/jira/browse/ARROW-2787?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Joseph Toth updated ARROW-2787:
-------------------------------
Description:
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();
}
}
was:
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();??
?? }??
??}??
> 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
> Affects Versions: 0.9.0
> Environment: clang6
> Reporter: Joseph Toth
> Priority: Major
>
> 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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