Coverage for python/lsst/daf/butler/delegates/arrownumpy.py: 45%

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1# This file is part of daf_butler. 

2# 

3# Developed for the LSST Data Management System. 

4# This product includes software developed by the LSST Project 

5# (http://www.lsst.org). 

6# See the COPYRIGHT file at the top-level directory of this distribution 

7# for details of code ownership. 

8# 

9# This software is dual licensed under the GNU General Public License and also 

10# under a 3-clause BSD license. Recipients may choose which of these licenses 

11# to use; please see the files gpl-3.0.txt and/or bsd_license.txt, 

12# respectively. If you choose the GPL option then the following text applies 

13# (but note that there is still no warranty even if you opt for BSD instead): 

14# 

15# This program is free software: you can redistribute it and/or modify 

16# it under the terms of the GNU General Public License as published by 

17# the Free Software Foundation, either version 3 of the License, or 

18# (at your option) any later version. 

19# 

20# This program is distributed in the hope that it will be useful, 

21# but WITHOUT ANY WARRANTY; without even the implied warranty of 

22# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 

23# GNU General Public License for more details. 

24# 

25# You should have received a copy of the GNU General Public License 

26# along with this program. If not, see <http://www.gnu.org/licenses/>. 

27 

28"""Support for reading numpy tables (structured 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 

37from lsst.utils.introspection import get_full_type_name 

38 

39from .arrowtable import ArrowTableDelegate 

40 

41__all__ = ["ArrowNumpyDelegate"] 

42 

43 

44class ArrowNumpyDelegate(ArrowTableDelegate): 

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

46 

47 _datasetType = np.ndarray 

48 

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

50 """Get a component from a numpy table stored via ArrowNumpy. 

51 

52 Parameters 

53 ---------- 

54 composite : `~numpy.ndarray` 

55 Numpy table to access component. 

56 componentName : `str` 

57 Name of component to retrieve. 

58 

59 Returns 

60 ------- 

61 component : `object` 

62 The component. 

63 

64 Raises 

65 ------ 

66 AttributeError 

67 The component can not be found. 

68 """ 

69 match componentName: 

70 case "columns": 

71 return list(composite.dtype.names) 

72 case "schema": 

73 return ArrowNumpySchema(composite.dtype) 

74 case "rowcount": 

75 return len(composite) 

76 

77 raise AttributeError( 

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

79 ) 

80 

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

82 return inMemoryDataset.dtype.names 

83 

84 def _selectColumns(self, inMemoryDataset: np.ndarray, columns: list[str]) -> np.ndarray: 

85 return inMemoryDataset[columns]