CLN: catch less inside try/except (#28203)

* CLN: catch less inside try/except

Author: jbrockmendel

pandas/_libs/reduction.pyx

@@ -296,8 +296,6 @@ cdef class SeriesBinGrouper:
                 islider.advance(group_size)
                 vslider.advance(group_size)
 
-        except:
-            raise
         finally:
             # so we don't free the wrong memory
             islider.reset()
@@ -425,8 +423,6 @@ cdef class SeriesGrouper:
 
                     group_size = 0
 
-        except:
-            raise
         finally:
             # so we don't free the wrong memory
             islider.reset()

pandas/core/groupby/generic.py

@@ -242,15 +242,18 @@ def aggregate(self, func, *args, **kwargs):
             # grouper specific aggregations
             if self.grouper.nkeys > 1:
                 return self._python_agg_general(func, *args, **kwargs)
+            elif args or kwargs:
+                result = self._aggregate_generic(func, *args, **kwargs)
             else:
 
                 # try to treat as if we are passing a list
                 try:
-                    assert not args and not kwargs
                     result = self._aggregate_multiple_funcs(
                         [func], _level=_level, _axis=self.axis
                     )
-
+                except Exception:
+                    result = self._aggregate_generic(func)
+                else:
                     result.columns = Index(
                         result.columns.levels[0], name=self._selected_obj.columns.name
                     )
@@ -260,8 +263,6 @@ def aggregate(self, func, *args, **kwargs):
                         # values. concat no longer converts DataFrame[Sparse]
                         # to SparseDataFrame, so we do it here.
                         result = SparseDataFrame(result._data)
-                except Exception:
-                    result = self._aggregate_generic(func, *args, **kwargs)
 
         if not self.as_index:
             self._insert_inaxis_grouper_inplace(result)
@@ -313,10 +314,10 @@ def _aggregate_item_by_item(self, func, *args, **kwargs):
         cannot_agg = []
         errors = None
         for item in obj:
-            try:
-                data = obj[item]
-                colg = SeriesGroupBy(data, selection=item, grouper=self.grouper)
+            data = obj[item]
+            colg = SeriesGroupBy(data, selection=item, grouper=self.grouper)
 
+            try:
                 cast = self._transform_should_cast(func)
 
                 result[item] = colg.aggregate(func, *args, **kwargs)
@@ -684,7 +685,7 @@ def _transform_item_by_item(self, obj, wrapper):
 
         return DataFrame(output, index=obj.index, columns=columns)
 
-    def filter(self, func, dropna=True, *args, **kwargs):  # noqa
+    def filter(self, func, dropna=True, *args, **kwargs):
         """
         Return a copy of a DataFrame excluding elements from groups that
         do not satisfy the boolean criterion specified by func.

pandas/core/groupby/groupby.py

@@ -653,7 +653,8 @@ def curried(x):
                     # mark this column as an error
                     try:
                         return self._aggregate_item_by_item(name, *args, **kwargs)
-                    except (AttributeError):
+                    except AttributeError:
+                        # e.g. SparseArray has no flags attr
                         raise ValueError
 
         return wrapper