fix(python): Address incorrect selector & col expansion (#19742)

py-polars/polars/selectors.py

@@ -385,10 +385,6 @@ def __and__(self, other: Any) -> Expr: ...
     def __and__(self, other: Any) -> SelectorType | Expr:
         if is_column(other):
             colname = other.meta.output_name()
-            if self._attrs["name"] == "by_name" and (
-                params := self._attrs["params"]
-            ).get("require_all", True):
-                return by_name(*params["*names"], colname)
             other = by_name(colname)
         if is_selector(other):
             return _selector_proxy_(
@@ -399,6 +395,12 @@ def __and__(self, other: Any) -> SelectorType | Expr:
         else:
             return self.as_expr().__and__(other)
 
+    def __rand__(self, other: Any) -> Expr:
+        if is_column(other):
+            colname = other.meta.output_name()
+            return by_name(colname) & self
+        return self.as_expr().__rand__(other)
+
     @overload
     def __or__(self, other: SelectorType) -> SelectorType: ...
 
@@ -417,6 +419,11 @@ def __or__(self, other: Any) -> SelectorType | Expr:
         else:
             return self.as_expr().__or__(other)
 
+    def __ror__(self, other: Any) -> Expr:
+        if is_column(other):
+            other = by_name(other.meta.output_name())
+        return self.as_expr().__ror__(other)
+
     @overload
     def __xor__(self, other: SelectorType) -> SelectorType: ...
 
@@ -435,21 +442,6 @@ def __xor__(self, other: Any) -> SelectorType | Expr:
         else:
             return self.as_expr().__or__(other)
 
-    def __rand__(self, other: Any) -> Expr:
-        if is_column(other):
-            colname = other.meta.output_name()
-            if self._attrs["name"] == "by_name" and (
-                params := self._attrs["params"]
-            ).get("require_all", True):
-                return by_name(colname, *params["*names"])
-            other = by_name(colname)
-        return self.as_expr().__rand__(other)
-
-    def __ror__(self, other: Any) -> Expr:
-        if is_column(other):
-            other = by_name(other.meta.output_name())
-        return self.as_expr().__ror__(other)
-
     def __rxor__(self, other: Any) -> Expr:
         if is_column(other):
             other = by_name(other.meta.output_name())

py-polars/tests/unit/test_selectors.py

@@ -182,11 +182,17 @@ def test_selector_by_name(df: pl.DataFrame) -> None:
 
     # check "by_name & col"
     for selector_expr, expected in (
-        (cs.by_name("abc", "cde") & pl.col("ghi"), ["abc", "cde", "ghi"]),
-        (pl.col("ghi") & cs.by_name("cde", "abc"), ["ghi", "cde", "abc"]),
+        (cs.by_name("abc", "cde") & pl.col("ghi"), []),
+        (cs.by_name("abc", "cde") & pl.col("cde"), ["cde"]),
+        (pl.col("cde") & cs.by_name("cde", "abc"), ["cde"]),
     ):
         assert df.select(selector_expr).columns == expected
 
+    # check "by_name & by_name"
+    assert df.select(
+        cs.by_name("abc", "cde", "def", "eee") & cs.by_name("cde", "eee", "fgg")
+    ).columns == ["cde", "eee"]
+
     # expected errors
     with pytest.raises(ColumnNotFoundError, match="xxx"):
         df.select(cs.by_name("xxx", "fgg", "!!!"))