Coverage for python/lsst/pipe/tasks/dataFrameActions/_evalColumnExpression.py: 59%
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1# This file is part of pipe_tasks.
2#
3# Developed for the LSST Data Management System.
4# This product includes software developed by the LSST Project
5# (https://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 <https://www.gnu.org/licenses/>.
22from __future__ import annotations
24__all__ = ("makeColumnExpressionAction", )
26import ast
27import operator as op
29from typing import Mapping, MutableMapping, Set, Type, Union, Optional, Any, Iterable
31from numpy import log10 as log
32from numpy import (cos, sin, cosh, sinh)
33import pandas as pd
35from ..configurableActions import ConfigurableActionField
36from ._baseDataFrameActions import DataFrameAction
39OPERATORS = {ast.Add: op.add, ast.Sub: op.sub, ast.Mult: op.mul,
40 ast.Div: op.truediv, ast.Pow: op.pow, ast.BitXor: op.xor,
41 ast.USub: op.neg}
43EXTRA_MATH = {"cos": cos, "sin": sin, "cosh": cosh, "sinh": sinh, "log": log}
46class ExpressionParser(ast.NodeVisitor):
47 def __init__(self, **kwargs):
48 self.variables = kwargs
49 self.variables['log'] = log
51 def visit_Name(self, node):
52 if node.id in self.variables:
53 return self.variables[node.id]
54 else:
55 return None
57 def visit_Num(self, node):
58 return node.n
60 def visit_NameConstant(self, node):
61 return node.value
63 def visit_UnaryOp(self, node):
64 val = self.visit(node.operand)
65 return OPERATORS[type(node.op)](val)
67 def visit_BinOp(self, node):
68 lhs = self.visit(node.left)
69 rhs = self.visit(node.right)
70 return OPERATORS[type(node.op)](lhs, rhs)
72 def visit_Call(self, node):
73 if node.func.id in self.variables:
74 function = self.visit(node.func)
75 return function(self.visit(node.args[0]))
76 else:
77 raise ValueError("String not recognized")
79 def generic_visit(self, node):
80 raise ValueError("String not recognized")
83def makeColumnExpressionAction(className: str, expr: str,
84 exprDefaults: Optional[Mapping[str, Union[DataFrameAction,
85 Type[DataFrameAction]]]] = None,
86 docstring: str = None
87 ) -> Type[DataFrameAction]:
88 node = ast.parse(expr, mode='eval')
90 # gather the specified names
91 names: Set[str] = set()
92 for elm in ast.walk(node):
93 if isinstance(elm, ast.Name):
94 names.add(elm.id)
96 # remove the known Math names
97 names -= EXTRA_MATH.keys()
99 fields: Mapping[str, ConfigurableActionField] = {}
100 for name in names:
101 if exprDefaults is not None and (value := exprDefaults.get(name)) is not None: 101 ↛ 104line 101 didn't jump to line 104, because the condition on line 101 was never false
102 kwargs = {"default": value}
103 else:
104 kwargs = {}
105 fields[name] = ConfigurableActionField(doc=f"expression action {name}", **kwargs)
107 # skip flake8 on N807 because this is a stand alone function, but it is
108 # intended to be patched in as a method on a dynamically generated class
109 def __call__(self, df: pd.DataFrame, **kwargs) -> pd.Series: # noqa: N807
110 values_map = {}
111 for name in fields:
112 values_map[name] = getattr(self, name)(df, **kwargs)
114 parser = ExpressionParser(**values_map)
115 return parser.visit(node.body)
117 # create the function to look up the columns for the dynamically created action
118 def columns(self) -> Iterable[str]:
119 for name in fields:
120 yield from getattr(self, name).columns
122 dct: MutableMapping[str, Any] = {"__call__": __call__, "columns": property(columns)}
123 if docstring is not None: 123 ↛ 125line 123 didn't jump to line 125, because the condition on line 123 was never false
124 dct['__doc__'] = docstring
125 dct.update(**fields)
127 return type(className, (DataFrameAction, ), dct)