feat: add to_frame method to solution

cobra/core/solution.py

@@ -10,7 +10,7 @@
 
 from numpy import empty, nan
 from optlang.interface import OPTIMAL
-from pandas import Series
+from pandas import Series, DataFrame
 
 from cobra.util.solver import check_solver_status
 
@@ -169,6 +169,11 @@ def y(self):
         warn("use solution.reduced_costs.values() instead", DeprecationWarning)
         return self.reduced_costs.values
 
+    def to_frame(self):
+        """Return the fluxes and reduced costs as a data frame"""
+        return DataFrame({'fluxes': self.fluxes,
+                          'reduced_costs': self.reduced_costs})
+
 
 class LegacySolution(object):
     """

cobra/test/test_model.py

@@ -6,6 +6,7 @@
 
 import numpy
 import pytest
+import pandas as pd
 from sympy import S
 
 import cobra.util.solver as su
@@ -733,6 +734,12 @@ def test_problem_properties(self, model):
         assert "test_variable" not in model.variables.keys()
         assert "test_constraint" not in model.variables.keys()
 
+    def test_solution_data_frame(self, model):
+        solution = model.optimize().to_frame()
+        assert isinstance(solution, pd.DataFrame)
+        assert 'fluxes' in solution
+        assert 'reduced_costs' in solution
+
     def test_model_medium(self, model):
         # Add a dummy 'malformed' import reaction
         bad_import = Reaction('bad_import')

release-notes/0.6.0.md

@@ -91,7 +91,9 @@ similar problem, we have completely refactored `cobra.Solution` so
 that `model.optimize()` now returns a solution and it is the user's
 responsibility to manage this object. `reaction.flux` gets its values
 directly from the `model.problem`. To sugar the new solution class,
-fluxes, reduced costs, and shadow prices are now pandas series!
+fluxes, reduced costs, and shadow prices are now pandas series! Fluxes
+and reduced costs can be returned as a data frame directlt with the
+`to_frame` method.
 
 ## Sampling