add Column.is_in

spec/API_specification/dataframe_api/column_object.py

@@ -384,3 +384,22 @@ def isnan(self) -> Column:
         Does *not* include 'missing' or 'null' entries.
         In particular, does not check for `np.timedelta64('NaT')`.
         """
+
+    def is_in(self, values: Column) -> Column[bool]:
+        """
+        Indicate whether the value at each row matches any value in `values`.
+
+        Parameters
+        ----------
+        values : Column
+            Contains values to compare against. May include ``float('nan')`` and
+            ``namespace.null``, which which case ``'nan'`` and ``null`` will
+            respectively return ``True`` even though ``float('nan') == float('nan')``
+            isn't ``True``.
+            The dtype of `values` must match the current column's dtype.
+
+        Returns
+        -------
+        Column[bool]
+        """
+        ...