REF: remove unnecessary _try_cast calls (pandas-dev#29642)

Author: jbrockmendel

pandas/core/groupby/generic.py

@@ -397,7 +397,7 @@ def _aggregate_named(self, func, *args, **kwargs):
             output = func(group, *args, **kwargs)
             if isinstance(output, (Series, Index, np.ndarray)):
                 raise ValueError("Must produce aggregated value")
-            result[name] = self._try_cast(output, group)
+            result[name] = output
 
         return result
 

pandas/core/groupby/groupby.py

@@ -1357,14 +1357,6 @@ def f(self, **kwargs):
 
                 # apply a non-cython aggregation
                 result = self.aggregate(lambda x: npfunc(x, axis=self.axis))
-
-                # coerce the resulting columns if we can
-                if isinstance(result, DataFrame):
-                    for col in result.columns:
-                        result[col] = self._try_cast(result[col], self.obj[col])
-                else:
-                    result = self._try_cast(result, self.obj)
-
                 return result
 
             set_function_name(f, name, cls)