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https://issues.apache.org/jira/browse/ARROW-1998?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16361526#comment-16361526
]
ASF GitHub Bot commented on ARROW-1998:
---------------------------------------
wesm commented on a change in pull request #1594: ARROW-1998: [Python] fix
crash on empty Numpy arrays
URL: https://github.com/apache/arrow/pull/1594#discussion_r167702409
##########
File path: cpp/src/arrow/python/numpy_to_arrow.cc
##########
@@ -850,16 +850,23 @@ Status NumPyConverter::ConvertObjectStrings() {
RETURN_NOT_OK(builder.Resize(length_));
bool global_have_bytes = false;
- int64_t offset = 0;
- while (offset < length_) {
- bool chunk_have_bytes = false;
- RETURN_NOT_OK(
- AppendObjectStrings(arr_, mask_, offset, &builder, &offset,
&chunk_have_bytes));
-
- global_have_bytes = global_have_bytes | chunk_have_bytes;
+ if (length_ == 0) {
+ // Produce an empty chunk
std::shared_ptr<Array> chunk;
RETURN_NOT_OK(builder.Finish(&chunk));
out_arrays_.emplace_back(std::move(chunk));
+ } else {
+ int64_t offset = 0;
+ while (offset < length_) {
+ bool chunk_have_bytes = false;
+ RETURN_NOT_OK(
+ AppendObjectStrings(arr_, mask_, offset, &builder, &offset,
&chunk_have_bytes));
+
+ global_have_bytes = global_have_bytes | chunk_have_bytes;
+ std::shared_ptr<Array> chunk;
+ RETURN_NOT_OK(builder.Finish(&chunk));
+ out_arrays_.emplace_back(std::move(chunk));
Review comment:
Could this be a `do ... while`?
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> [Python] Table.from_pandas crashes when data frame is empty
> -----------------------------------------------------------
>
> Key: ARROW-1998
> URL: https://issues.apache.org/jira/browse/ARROW-1998
> Project: Apache Arrow
> Issue Type: Bug
> Components: Python
> Affects Versions: 0.8.0
> Environment: Windows 10 Build 15063.850
> Python: 3.6.3
> Numpy: 1.14.0
> Pandas: 0.22.0
> Reporter: Victor Jimenez
> Assignee: Antoine Pitrou
> Priority: Major
> Labels: pull-request-available
> Fix For: 0.9.0
>
>
> Loading an empty CSV file, and then attempting to create a PyArrow Table from
> it makes the application crash. The following code should be able to
> reproduce the issue:
> {code}
> import numpy as np
> import pandas as pd
> import pyarrow as pa
> FIELDS = ['id', 'name']
> NUMPY_TYPES = {
> 'id': np.int64,
> 'name': np.unicode
> }
> PYARROW_SCHEMA = pa.schema([
> pa.field('id', pa.int64()),
> pa.field('name', pa.string())
> ])
> file = open('input.csv', 'w')
> file.close()
> df = pd.read_csv(
> 'input.csv',
> header=None,
> names=FIELDS,
> dtype=NUMPY_TYPES,
> engine='c',
> )
> pa.Table.from_pandas(df, schema=PYARROW_SCHEMA)
> {code}
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