CLN: Exception in nanops (#28433)

Author: jbrockmendel

pandas/core/nanops.py

@@ -1300,10 +1300,12 @@ def _ensure_numeric(x):
     elif not (is_float(x) or is_integer(x) or is_complex(x)):
         try:
             x = float(x)
-        except Exception:
+        except ValueError:
+            # e.g. "1+1j" or "foo"
             try:
                 x = complex(x)
-            except Exception:
+            except ValueError:
+                # e.g. "foo"
                 raise TypeError(
                     "Could not convert {value!s} to numeric".format(value=x)
                 )

pandas/tests/test_nanops.py

@@ -911,10 +911,11 @@ def test_non_convertable_values(self):
         msg = "Could not convert foo to numeric"
         with pytest.raises(TypeError, match=msg):
             nanops._ensure_numeric("foo")
-        msg = "Could not convert {} to numeric"
+
+        # with the wrong type, python raises TypeError for us
+        msg = "argument must be a string or a number"
         with pytest.raises(TypeError, match=msg):
             nanops._ensure_numeric({})
-        msg = r"Could not convert \[\] to numeric"
         with pytest.raises(TypeError, match=msg):
             nanops._ensure_numeric([])