add __pandas_priority__ to linopy objects (#389)

Author: FabianHofmann

doc/release_notes.rst

@@ -4,9 +4,9 @@ Release Notes
 Upcoming Version
 ----------------
 
+* Added a pandas priority attribute. With this change, the operation with pandas objects is now prioritizing linopy objects over pandas objects. This is useful when the using linopy objects in arithmetic operations with pandas objects, e.g. `a * x` where `a` is a pandas Series/DataFrame and `x` is a linopy variable.
 * The method :meth:`model.to_file <linopy.model.Model.to_file>` now includes a progress argument to enable or disable the progress bar while writing.
 
-
 Version 0.4.2
 --------------
 

linopy/expressions.py

@@ -344,6 +344,7 @@ class LinearExpression:
     __slots__ = ("_data", "_model")
     __array_ufunc__ = None
     __array_priority__ = 10000
+    __pandas_priority__ = 10000
 
     _fill_value = FILL_VALUE
 
@@ -1485,6 +1486,7 @@ class QuadraticExpression(LinearExpression):
     __slots__ = ("_data", "_model")
     __array_ufunc__ = None
     __array_priority__ = 10000
+    __pandas_priority__ = 10000
 
     _fill_value = {"vars": -1, "coeffs": np.nan, "const": np.nan}
 

linopy/objective.py

@@ -53,6 +53,7 @@ class Objective:
     __slots__ = ("_expression", "_model", "_sense", "_value")
     __array_ufunc__ = None
     __array_priority__ = 10000
+    __pandas_priority__ = 10000
 
     _fill_value = {"vars": -1, "coeffs": np.nan, "const": 0}
 

linopy/variables.py

@@ -143,6 +143,8 @@ class Variable:
 
     __slots__ = ("_data", "_model")
     __array_ufunc__ = None
+    __array_priority__ = 10000
+    __pandas_priority__ = 10000
 
     _fill_value = FILL_VALUE
 

test/test_linear_expression.py

@@ -199,6 +199,9 @@ def test_linear_expression_with_multiplication(x):
     expr = xr.DataArray(np.array([[1, 2], [2, 3]])) * x
     assert isinstance(expr, LinearExpression)
 
+    expr = pd.Series([1, 2], index=pd.RangeIndex(2, name="dim_0")) * x
+    assert isinstance(expr, LinearExpression)
+
 
 def test_linear_expression_with_addition(m, x, y):
     expr = 10 * x + y