Coverage for python/lsst/daf/butler/delegates/arrownumpydict.py: 94%

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27 

28"""Support for reading dictionaries of numpy arrays with the Arrow 

29formatter. 

30""" 

31from __future__ import annotations 

32 

33from typing import Any 

34 

35import numpy as np 

36from lsst.daf.butler.formatters.parquet import ArrowNumpySchema, _numpy_dict_to_dtype 

37from lsst.utils.introspection import get_full_type_name 

38 

39from .arrowtable import ArrowTableDelegate 

40 

41__all__ = ["ArrowNumpyDictDelegate"] 

42 

43 

44class ArrowNumpyDictDelegate(ArrowTableDelegate): 

45 """Delegate that understands the ``ArrowNumpyDict`` storage class.""" 

46 

47 _datasetType = dict 

48 

49 def getComponent(self, composite: dict[str, np.ndarray], componentName: str) -> Any: 

50 """Get a component from a dict of numpy arrays stored via 

51 ArrowNumpyDict. 

52 

53 Parameters 

54 ---------- 

55 composite : `~numpy.ndarray` 

56 Numpy table to access component. 

57 componentName : `str` 

58 Name of component to retrieve. 

59 

60 Returns 

61 ------- 

62 component : `object` 

63 The component. 

64 

65 Raises 

66 ------ 

67 AttributeError 

68 The component can not be found. 

69 """ 

70 match componentName: 

71 case "columns": 

72 return list(composite.keys()) 

73 case "schema": 

74 dtype, _ = _numpy_dict_to_dtype(composite) 

75 return ArrowNumpySchema(dtype) 

76 case "rowcount": 76 ↛ 79line 76 didn't jump to line 79, because the pattern on line 76 never matched

77 return len(composite[list(composite.keys())[0]]) 

78 

79 raise AttributeError( 

80 f"Do not know how to retrieve component {componentName} from {get_full_type_name(composite)}" 

81 ) 

82 

83 def _getColumns(self, inMemoryDataset: dict[str, np.ndarray]) -> list[str]: 

84 return list(inMemoryDataset.keys()) 

85 

86 def _selectColumns( 

87 self, inMemoryDataset: dict[str, np.ndarray], columns: list[str] 

88 ) -> dict[str, np.ndarray]: 

89 return {column: inMemoryDataset[column] for column in columns}