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PERF: avoid NumPy fallback when casting Arrow int/string to string #63401

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PERF: avoid NumPy fallback when casting Arrow int/string to string #63401

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17 changes: 17 additions & 0 deletions pandas/core/arrays/string_arrow.py
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Original file line number Diff line number Diff line change
Expand Up @@ -210,6 +210,23 @@ def _from_sequence(
result = scalars._data
result = lib.ensure_string_array(result, copy=copy, convert_na_value=False)
pa_arr = pa.array(result, mask=na_values, type=pa.large_string())
elif isinstance(scalars, ArrowExtensionArray):
pa_type = scalars._pa_array.type
# Use PyArrow's native cast for integer and string types where
# the string representation matches Python's str().
# Float and boolean have different representations in PyArrow
# (e.g., 1.0 -> "1" instead of "1.0", True -> "true" instead of "True")
if (
pa.types.is_integer(pa_type)
or pa.types.is_large_string(pa_type)
or pa.types.is_string(pa_type)
):
pa_arr = pc.cast(scalars._pa_array, pa.large_string())
else:
# Fall back for types where PyArrow's string representation
# differs from Python's str()
result = lib.ensure_string_array(scalars, copy=copy)
pa_arr = pa.array(result, type=pa.large_string(), from_pandas=True)
elif isinstance(scalars, (pa.Array, pa.ChunkedArray)):
pa_arr = pc.cast(scalars, pa.large_string())
else:
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