Coverage for python/lsst/daf/butler/delegates/arrownumpy.py: 45%
23 statements
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« prev ^ index » next coverage.py v7.2.3, created at 2023-04-22 02:18 -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 program is free software: you can redistribute it and/or modify
10# it under the terms of the GNU General Public License as published by
11# the Free Software Foundation, either version 3 of the License, or
12# (at your option) any later version.
13#
14# This program is distributed in the hope that it will be useful,
15# but WITHOUT ANY WARRANTY; without even the implied warranty of
16# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17# GNU General Public License for more details.
18#
19# You should have received a copy of the GNU General Public License
20# along with this program. If not, see <http://www.gnu.org/licenses/>.
22"""Support for reading numpy tables (structured arrays) with the Arrow
23formatter.
24"""
25from __future__ import annotations
27from typing import Any
29import numpy as np
30from lsst.daf.butler.formatters.parquet import ArrowNumpySchema
31from lsst.utils.introspection import get_full_type_name
33from .arrowtable import ArrowTableDelegate
35__all__ = ["ArrowNumpyDelegate"]
38class ArrowNumpyDelegate(ArrowTableDelegate):
39 _datasetType = np.ndarray
41 def getComponent(self, composite: np.ndarray, componentName: str) -> Any:
42 """Get a component from a numpy table stored via ArrowNumpy.
44 Parameters
45 ----------
46 composite : `~numpy.ndarray`
47 Numpy table to access component.
48 componentName : `str`
49 Name of component to retrieve.
51 Returns
52 -------
53 component : `object`
54 The component.
56 Raises
57 ------
58 AttributeError
59 The component can not be found.
60 """
61 match componentName:
62 case "columns":
63 return list(composite.dtype.names)
64 case "schema":
65 return ArrowNumpySchema(composite.dtype)
66 case "rowcount":
67 return len(composite)
69 raise AttributeError(
70 f"Do not know how to retrieve component {componentName} from {get_full_type_name(composite)}"
71 )
73 def _getColumns(self, inMemoryDataset: np.ndarray) -> list[str]:
74 return inMemoryDataset.dtype.names
76 def _selectColumns(self, inMemoryDataset: np.ndarray, columns: list[str]) -> np.ndarray:
77 return inMemoryDataset[columns]