feat: Support string matching in local executor

bigframes/core/compile/polars/compiler.py

@@ -301,6 +301,34 @@ def _(self, op: ops.ScalarOp, l_input: pl.Expr, r_input: pl.Expr) -> pl.Expr:
             assert isinstance(op, string_ops.StrConcatOp)
             return pl.concat_str(l_input, r_input)
 
+        @compile_op.register(string_ops.StrContainsOp)
+        def _(self, op: ops.ScalarOp, input: pl.Expr) -> pl.Expr:
+            assert isinstance(op, string_ops.StrContainsOp)
+            return input.str.contains(pattern=op.pat, literal=True)
+
+        @compile_op.register(string_ops.StrContainsRegexOp)
+        def _(self, op: ops.ScalarOp, input: pl.Expr) -> pl.Expr:
+            assert isinstance(op, string_ops.StrContainsRegexOp)
+            return input.str.contains(pattern=op.pat, literal=False)
+
+        @compile_op.register(string_ops.StartsWithOp)
+        def _(self, op: ops.ScalarOp, input: pl.Expr) -> pl.Expr:
+            assert isinstance(op, string_ops.StartsWithOp)
+            if len(op.pat) == 1:
+                return input.str.starts_with(op.pat[0])
+            else:
+                return pl.any_horizontal(
+                    *(input.str.starts_with(pat) for pat in op.pat)
+                )
+
+        @compile_op.register(string_ops.EndsWithOp)
+        def _(self, op: ops.ScalarOp, input: pl.Expr) -> pl.Expr:
+            assert isinstance(op, string_ops.EndsWithOp)
+            if len(op.pat) == 1:
+                return input.str.ends_with(op.pat[0])
+            else:
+                return pl.any_horizontal(*(input.str.ends_with(pat) for pat in op.pat))
+
         @compile_op.register(dt_ops.StrftimeOp)
         def _(self, op: ops.ScalarOp, input: pl.Expr) -> pl.Expr:
             assert isinstance(op, dt_ops.StrftimeOp)

bigframes/session/polars_executor.py

@@ -21,7 +21,13 @@
 from bigframes.core import array_value, bigframe_node, expression, local_data, nodes
 import bigframes.operations
 from bigframes.operations import aggregations as agg_ops
-from bigframes.operations import bool_ops, comparison_ops, generic_ops, numeric_ops
+from bigframes.operations import (
+    bool_ops,
+    comparison_ops,
+    generic_ops,
+    numeric_ops,
+    string_ops,
+)
 from bigframes.session import executor, semi_executor
 
 if TYPE_CHECKING:
@@ -69,6 +75,10 @@
     generic_ops.IsInOp,
     generic_ops.IsNullOp,
     generic_ops.NotNullOp,
+    string_ops.StartsWithOp,
+    string_ops.EndsWithOp,
+    string_ops.StrContainsOp,
+    string_ops.StrContainsRegexOp,
 )
 _COMPATIBLE_AGG_OPS = (
     agg_ops.SizeOp,

tests/system/small/engines/test_strings.py

@@ -0,0 +1,77 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import pytest
+
+from bigframes.core import array_value
+import bigframes.operations as ops
+from bigframes.session import polars_executor
+from bigframes.testing.engine_utils import assert_equivalence_execution
+
+pytest.importorskip("polars")
+
+# Polars used as reference as its fast and local. Generally though, prefer gbq engine where they disagree.
+REFERENCE_ENGINE = polars_executor.PolarsExecutor()
+
+
+@pytest.mark.parametrize("engine", ["polars", "bq"], indirect=True)
+def test_engines_str_contains(scalars_array_value: array_value.ArrayValue, engine):
+    arr, _ = scalars_array_value.compute_values(
+        [
+            ops.StrContainsOp("(?i)hEllo").as_expr("string_col"),
+            ops.StrContainsOp("Hello").as_expr("string_col"),
+            ops.StrContainsOp("T").as_expr("string_col"),
+            ops.StrContainsOp(".*").as_expr("string_col"),
+        ]
+    )
+    assert_equivalence_execution(arr.node, REFERENCE_ENGINE, engine)
+
+
+@pytest.mark.parametrize("engine", ["polars", "bq"], indirect=True)
+def test_engines_str_contains_regex(
+    scalars_array_value: array_value.ArrayValue, engine
+):
+    arr, _ = scalars_array_value.compute_values(
+        [
+            ops.StrContainsRegexOp("(?i)hEllo").as_expr("string_col"),
+            ops.StrContainsRegexOp("Hello").as_expr("string_col"),
+            ops.StrContainsRegexOp("T").as_expr("string_col"),
+            ops.StrContainsRegexOp(".*").as_expr("string_col"),
+        ]
+    )
+    assert_equivalence_execution(arr.node, REFERENCE_ENGINE, engine)
+
+
+@pytest.mark.parametrize("engine", ["polars", "bq"], indirect=True)
+def test_engines_str_startswith(scalars_array_value: array_value.ArrayValue, engine):
+    arr, _ = scalars_array_value.compute_values(
+        [
+            ops.StartsWithOp("He").as_expr("string_col"),
+            ops.StartsWithOp("llo").as_expr("string_col"),
+            ops.StartsWithOp(("He", "T", "ca")).as_expr("string_col"),
+        ]
+    )
+    assert_equivalence_execution(arr.node, REFERENCE_ENGINE, engine)
+
+
+@pytest.mark.parametrize("engine", ["polars", "bq"], indirect=True)
+def test_engines_str_endswith(scalars_array_value: array_value.ArrayValue, engine):
+    arr, _ = scalars_array_value.compute_values(
+        [
+            ops.EndsWithOp("!").as_expr("string_col"),
+            ops.EndsWithOp("llo").as_expr("string_col"),
+            ops.EndsWithOp(("He", "T", "ca")).as_expr("string_col"),
+        ]
+    )
+    assert_equivalence_execution(arr.node, REFERENCE_ENGINE, engine)