Coverage for python/lsst/daf/butler/delegates/arrownumpy.py: 45%
23 statements
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« prev ^ index » next coverage.py v7.5.0, created at 2024-04-26 02:47 -0700
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/>.
28"""Support for reading numpy tables (structured arrays) with the Arrow
29formatter.
30"""
31from __future__ import annotations
33from typing import Any
35import numpy as np
36from lsst.daf.butler.formatters.parquet import ArrowNumpySchema
37from lsst.utils.introspection import get_full_type_name
39from .arrowtable import ArrowTableDelegate
41__all__ = ["ArrowNumpyDelegate"]
44class ArrowNumpyDelegate(ArrowTableDelegate):
45 """Delegate that understands the ``ArrowNumpy`` storage class."""
47 _datasetType = np.ndarray
49 def getComponent(self, composite: np.ndarray, componentName: str) -> Any:
50 """Get a component from a numpy table stored via ArrowNumpy.
52 Parameters
53 ----------
54 composite : `~numpy.ndarray`
55 Numpy table to access component.
56 componentName : `str`
57 Name of component to retrieve.
59 Returns
60 -------
61 component : `object`
62 The component.
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)
77 raise AttributeError(
78 f"Do not know how to retrieve component {componentName} from {get_full_type_name(composite)}"
79 )
81 def _getColumns(self, inMemoryDataset: np.ndarray) -> list[str]:
82 return inMemoryDataset.dtype.names
84 def _selectColumns(self, inMemoryDataset: np.ndarray, columns: list[str]) -> np.ndarray:
85 return inMemoryDataset[columns]