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PERF: Bypass chunking/validation logic in StringDtype__from_arrow__ #47781

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Merged
merged 10 commits into from
Feb 24, 2023
Merged

PERF: Bypass chunking/validation logic in StringDtype__from_arrow__ #47781

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d63037d
Bypass chunking/validation logic in __from_arrow__
timlod Jul 18, 2022
9bb0312
Handle zero-chunks correctly & convert None to NA
timlod Jul 18, 2022
b538260
Add change to whatsnew
timlod Jul 18, 2022
9f102af
Merge branch 'main' into opt-stringarray-from-arrow
timlod Oct 22, 2022
7176086
Add to v2 whatsnew
timlod Oct 23, 2022
3d1162e
Add GH issue to comment about validation bypass
timlod Nov 30, 2022
c2d131a
Add # to GH issue
timlod Nov 30, 2022
e5028ff
Merge branch 'main' into opt-stringarray-from-arrow
timlod Jan 28, 2023
af5fbef
Merge branch 'main' into opt-stringarray-from-arrow
timlod Feb 24, 2023
563e247
Move release note to v2.1.0
timlod Feb 24, 2023
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1 change: 1 addition & 0 deletions doc/source/whatsnew/v2.1.0.rst
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Expand Up @@ -102,6 +102,7 @@ Performance improvements
~~~~~~~~~~~~~~~~~~~~~~~~
- Performance improvement in :meth:`DataFrame.first_valid_index` and :meth:`DataFrame.last_valid_index` for extension array dtypes (:issue:`51549`)
- Performance improvement in :meth:`DataFrame.clip` and :meth:`Series.clip` (:issue:`51472`)
- Performance improvement in :func:`read_parquet` on string columns when using ``use_nullable_dtypes=True`` (:issue:`47345`)
-

.. ---------------------------------------------------------------------------
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21 changes: 12 additions & 9 deletions pandas/core/arrays/string_.py
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Expand Up @@ -203,16 +203,19 @@ def __from_arrow__(
# pyarrow.ChunkedArray
chunks = array.chunks

results = []
for arr in chunks:
# using _from_sequence to ensure None is converted to NA
str_arr = StringArray._from_sequence(np.array(arr))
results.append(str_arr)

if results:
return StringArray._concat_same_type(results)
if len(chunks) == 0:
arr = np.array([], dtype=object)
else:
return StringArray(np.array([], dtype="object"))
arr = pyarrow.concat_arrays(chunks).to_numpy(zero_copy_only=False)
arr = lib.convert_nans_to_NA(arr)
# Bypass validation inside StringArray constructor, see GH#47781
new_string_array = StringArray.__new__(StringArray)
NDArrayBacked.__init__(
new_string_array,
arr,
StringDtype(storage="python"),
)
return new_string_array


class BaseStringArray(ExtensionArray):
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