[GitHub] [arrow] jorisvandenbossche commented on a diff in pull request #13075: ARROW-16467: [Python] Add helper function _exec_plan._filter_table to filter tables based on Expression

[GitBox <gi...@apache.org>]

jorisvandenbossche commented on code in PR #13075:
URL: https://github.com/apache/arrow/pull/13075#discussion_r868086017


##########
python/pyarrow/tests/test_exec_plan.py:
##########
@@ -190,3 +191,35 @@ def test_table_join_keys_order():
         "colVals_l": ["a", "b", "f", None],
         "colVals_r": ["A", "B", None, "Z"],
     })
+
+
+@pytest.mark.parametrize("use_datasets", [False, True])
+def test_filter_table(use_datasets):
+    t = pa.table({
+        "a": [1, 2, 3, 4, 5],
+        "b": [10, 20, 30, 40, 50]
+    })
+    if use_datasets:
+        t = ds.dataset([t])
+
+    result = ep._filter_table(
+        t, (pc.field("a") <= pc.scalar(3)) & (pc.field("b") == pc.scalar(20)),
+        output_type=pa.Table if not use_datasets else ds.InMemoryDataset
+    )
+    if use_datasets:
+        result = result.to_table()
+    assert result == pa.table({
+        "a": [2],
+        "b": [20]
+    })
+
+    result = ep._filter_table(
+        t, pc.field("b") > pc.scalar(30),
+        output_type=pa.Table if not use_datasets else ds.InMemoryDataset
+    )
+    if use_datasets:
+        result = result.to_table()
+    assert result == pa.table({
+        "a": [4, 5],
+        "b": [40, 50]
+    })

Review Comment:
   Maybe add a small check that ensures a proper error is raised (and eg no segfault) if 1) passing an expressions that doesn't return a boolean value, 2) passing an expression referencing a non-existing field name



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