[Data] Add namespaced expressions that expose pyarrow functions

doc/source/conf.py

@@ -650,6 +650,7 @@ def filter(self, record):
     "numpy",
     "pandas",
     "pyarrow",
+    "pyarrow.compute",
     "pytorch_lightning",
     "scipy",
     "setproctitle",

doc/source/data/api/expressions.rst

@@ -39,4 +39,22 @@ instantiate them directly, but you may encounter them when working with expressi
     BinaryExpr
     UnaryExpr
     UDFExpr
-    StarExpr
+    StarExpr
+
+Expression namespaces
+------------------------------------
+
+These namespace classes provide specialized operations for list, string, and struct columns.
+You access them through properties on expressions: ``.list``, ``.str``, and ``.struct``.
+
+.. autoclass:: _ListNamespace
+    :members:
+    :exclude-members: _expr
+
+.. autoclass:: _StringNamespace
+    :members:
+    :exclude-members: _expr
+
+.. autoclass:: _StructNamespace
+    :members:
+    :exclude-members: _expr

python/ray/data/BUILD.bazel

@@ -1635,6 +1635,20 @@ py_test(
     ],
 )
 
+py_test(
+    name = "test_namespace_expressions",
+    size = "medium",
+    srcs = ["tests/test_namespace_expressions.py"],
+    tags = [
+        "exclusive",
+        "team:data",
+    ],
+    deps = [
+        ":conftest",
+        "//:ray_lib",
+    ],
+)
+
 py_test(
     name = "test_context",
     size = "small",