DEPR: float/int(Series[single_elemet])

doc/source/whatsnew/v2.0.0.rst

@@ -756,7 +756,7 @@ Deprecations
 - :meth:`Index.is_object` has been deprecated. Use :func:`pandas.api.types.is_object_dtype` instead (:issue:`50042`)
 - :meth:`Index.is_interval` has been deprecated. Use :func:`pandas.api.types.is_intterval_dtype` instead (:issue:`50042`)
 - Deprecated ``all`` and ``any`` reductions with ``datetime64`` and :class:`DatetimeTZDtype` dtypes, use e.g. ``(obj != pd.Timestamp(0), tz=obj.tz).all()`` instead (:issue:`34479`)
--
+- Deprecated calling ``float`` or ``int`` on a single element :class:`Series` to return a ``float`` or ``int`` respectively. Extract the element before calling ``float`` or ``int`` instead (:issue:`51101`)
 
 .. ---------------------------------------------------------------------------
 .. _whatsnew_200.prior_deprecations:

pandas/core/series.py

@@ -19,6 +19,7 @@
     cast,
     overload,
 )
+import warnings
 import weakref
 
 import numpy as np
@@ -81,6 +82,7 @@
     Substitution,
     doc,
 )
+from pandas.util._exceptions import find_stack_level
 from pandas.util._validators import (
     validate_ascending,
     validate_bool_kwarg,
@@ -216,6 +218,13 @@ def _coerce_method(converter):
 
     def wrapper(self):
         if len(self) == 1:
+            warnings.warn(
+                f"Calling {converter.__name__} on a single element Series is "
+                "deprecated and will raise a TypeError in the future. "
+                f"Use {converter.__name__}(ser.iloc[0]) instead",
+                FutureWarning,
+                stacklevel=find_stack_level(),
+            )
             return converter(self.iloc[0])
         raise TypeError(f"cannot convert the series to {converter}")
 

pandas/tests/series/test_api.py

@@ -287,3 +287,10 @@ def test_numeric_only(self, kernel, has_numeric_only, dtype):
             else:
                 # reducer
                 assert result == expected
+
+
+@pytest.mark.parametrize("converter", [int, float])
+def test_float_int_deprecated(converter):
+    # GH 51101
+    with tm.assert_produces_warning(FutureWarning):
+        assert converter(Series([1])) == converter(1)