[GitHub] [arrow] jorisvandenbossche commented on a change in pull request #7691: ARROW-8655: [Python][Dataset] Provide helper method to get keys from a partition expression

[GitBox <gi...@apache.org>]

jorisvandenbossche commented on a change in pull request #7691:
URL: https://github.com/apache/arrow/pull/7691#discussion_r452446416



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File path: python/pyarrow/includes/libarrow_dataset.pxd
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@@ -314,6 +314,10 @@ cdef extern from "arrow/dataset/api.h" namespace "arrow::dataset" nogil:
             const CExpression& partition_expression,
             CRecordBatchProjector* projector)
 
+    cdef CResult[unordered_map[c_string, shared_ptr[CScalar]]] \
+        CGetPartitionKeys "arrow::dataset::KeyValuePartitioning::GetKeys"(

Review comment:
       One question for my education: `GetKeys` is a method on the `KeyValuePartitioning` class, but since that method doesn't use any of the initialized variabled of the object, you can just use it as a free function like this independent from a KeyValuePartitioning object in C++? (like a static/class method in Python, but then without needing to mark it as such)




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