ERR: Improve error message in validate_percentile (#51475)

Author: ShashwatAgrawal20

pandas/tests/series/methods/test_quantile.py

@@ -43,6 +43,11 @@ def test_quantile(self, datetime_series):
             with pytest.raises(ValueError, match=msg):
                 datetime_series.quantile(invalid)
 
+        s = Series(np.random.randn(100))
+        percentile_array = [-0.5, 0.25, 1.5]
+        with pytest.raises(ValueError, match=msg):
+            s.quantile(percentile_array)
+
     def test_quantile_multi(self, datetime_series):
         qs = [0.1, 0.9]
         result = datetime_series.quantile(qs)

pandas/util/_validators.py

@@ -329,12 +329,13 @@ def validate_percentile(q: float | Iterable[float]) -> np.ndarray:
     q_arr = np.asarray(q)
     # Don't change this to an f-string. The string formatting
     # is too expensive for cases where we don't need it.
-    msg = "percentiles should all be in the interval [0, 1]. Try {} instead."
+    msg = "percentiles should all be in the interval [0, 1]"
     if q_arr.ndim == 0:
         if not 0 <= q_arr <= 1:
-            raise ValueError(msg.format(q_arr / 100.0))
-    elif not all(0 <= qs <= 1 for qs in q_arr):
-        raise ValueError(msg.format(q_arr / 100.0))
+            raise ValueError(msg)
+    else:
+        if not all(0 <= qs <= 1 for qs in q_arr):
+            raise ValueError(msg)
     return q_arr