Construct a pandas Block from the `item` dictionary coming from pyarrow's serialization or returned by arrow::python::ConvertTableToPandas. This function takes care of converting dictionary types to pandas categorical, Timestamp-with-timezones to the proper pandas Block, and co
(item, columns=None, extension_columns=None, return_block=True)
| 721 | |
| 722 | |
| 723 | def _reconstruct_block(item, columns=None, extension_columns=None, return_block=True): |
| 724 | """ |
| 725 | Construct a pandas Block from the `item` dictionary coming from pyarrow's |
| 726 | serialization or returned by arrow::python::ConvertTableToPandas. |
| 727 | |
| 728 | This function takes care of converting dictionary types to pandas |
| 729 | categorical, Timestamp-with-timezones to the proper pandas Block, and |
| 730 | conversion to pandas ExtensionBlock |
| 731 | |
| 732 | Parameters |
| 733 | ---------- |
| 734 | item : dict |
| 735 | For basic types, this is a dictionary in the form of |
| 736 | {'block': np.ndarray of values, 'placement': pandas block placement}. |
| 737 | Additional keys are present for other types (dictionary, timezone, |
| 738 | object). |
| 739 | columns : |
| 740 | Column names of the table being constructed, used for extension types |
| 741 | extension_columns : dict |
| 742 | Dictionary of {column_name: pandas_dtype} that includes all columns |
| 743 | and corresponding dtypes that will be converted to a pandas |
| 744 | ExtensionBlock. |
| 745 | |
| 746 | Returns |
| 747 | ------- |
| 748 | pandas Block |
| 749 | |
| 750 | """ |
| 751 | import pandas.core.internals as _int |
| 752 | |
| 753 | block_arr = item.get('block', None) |
| 754 | placement = item['placement'] |
| 755 | if 'dictionary' in item: |
| 756 | arr = _pandas_api.categorical_type.from_codes( |
| 757 | block_arr, categories=item['dictionary'], |
| 758 | ordered=item['ordered']) |
| 759 | elif 'timezone' in item: |
| 760 | unit, _ = np.datetime_data(block_arr.dtype) |
| 761 | dtype = make_datetimetz(unit, item['timezone']) |
| 762 | if _pandas_api.is_ge_v21(): |
| 763 | arr = _pandas_api.pd.array( |
| 764 | block_arr.view("int64"), dtype=dtype, copy=False |
| 765 | ) |
| 766 | else: |
| 767 | arr = block_arr |
| 768 | if return_block: |
| 769 | block = _int.make_block(block_arr, placement=placement, |
| 770 | klass=_int.DatetimeTZBlock, |
| 771 | dtype=dtype) |
| 772 | return block |
| 773 | elif 'py_array' in item: |
| 774 | # create ExtensionBlock |
| 775 | arr = item['py_array'] |
| 776 | assert len(placement) == 1 |
| 777 | name = columns[placement[0]] |
| 778 | pandas_dtype = extension_columns[name] |
| 779 | if not hasattr(pandas_dtype, '__from_arrow__'): |
| 780 | raise ValueError("This column does not support to be converted " |
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