Coverage for python/lsst/daf/butler/delegates/arrownumpy.py: 45%
23 statements
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« prev ^ index » next coverage.py v7.2.7, created at 2023-07-21 09:55 +0000
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 """Delegate that understands the ``ArrowNumpy`` storage class."""
41 _datasetType = np.ndarray
43 def getComponent(self, composite: np.ndarray, componentName: str) -> Any:
44 """Get a component from a numpy table stored via ArrowNumpy.
46 Parameters
47 ----------
48 composite : `~numpy.ndarray`
49 Numpy table to access component.
50 componentName : `str`
51 Name of component to retrieve.
53 Returns
54 -------
55 component : `object`
56 The component.
58 Raises
59 ------
60 AttributeError
61 The component can not be found.
62 """
63 match componentName:
64 case "columns":
65 return list(composite.dtype.names)
66 case "schema":
67 return ArrowNumpySchema(composite.dtype)
68 case "rowcount":
69 return len(composite)
71 raise AttributeError(
72 f"Do not know how to retrieve component {componentName} from {get_full_type_name(composite)}"
73 )
75 def _getColumns(self, inMemoryDataset: np.ndarray) -> list[str]:
76 return inMemoryDataset.dtype.names
78 def _selectColumns(self, inMemoryDataset: np.ndarray, columns: list[str]) -> np.ndarray:
79 return inMemoryDataset[columns]