Coverage for python/lsst/daf/butler/delegates/arrowastropy.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 Astropy tables with the Arrow formatter.""" 

29from __future__ import annotations 

30 

31from typing import Any 

32 

33import astropy.table as atable 

34from lsst.daf.butler.formatters.parquet import ArrowAstropySchema 

35from lsst.utils.introspection import get_full_type_name 

36 

37from .arrowtable import ArrowTableDelegate 

38 

39__all__ = ["ArrowAstropyDelegate"] 

40 

41 

42class ArrowAstropyDelegate(ArrowTableDelegate): 

43 """Delegate that understands the ``ArrowAstropy`` storage class.""" 

44 

45 _datasetType = atable.Table 

46 

47 def getComponent(self, composite: atable.Table, componentName: str) -> Any: 

48 """Get a component from an astropy table stored via ArrowAstropy. 

49 

50 Parameters 

51 ---------- 

52 composite : `~astropy.table.Table` 

53 Astropy table to access component. 

54 componentName : `str` 

55 Name of component to retrieve. 

56 

57 Returns 

58 ------- 

59 component : `object` 

60 The component. 

61 

62 Raises 

63 ------ 

64 AttributeError 

65 The component can not be found. 

66 """ 

67 match componentName: 

68 case "columns": 

69 return list(composite.columns.keys()) 

70 case "schema": 

71 return ArrowAstropySchema(composite) 

72 case "rowcount": 

73 return len(composite) 

74 

75 raise AttributeError( 

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

77 ) 

78 

79 def _getColumns(self, inMemoryDataset: atable.Table) -> list[str]: 

80 return inMemoryDataset.columns.keys() 

81 

82 def _selectColumns(self, inMemoryDataset: atable.Table, columns: list[str]) -> atable.Table: 

83 return inMemoryDataset[columns]