[SPARK-19429][PYTHON][SQL] Support slice arguments in Column.__getitem__

## What changes were proposed in this pull request?

- Add support for `slice` arguments in `Column.__getitem__`.
- Remove obsolete `__getslice__` bindings.

## How was this patch tested?

Existing unit tests, additional tests covering `[]` with `slice`.

Author: zero323 <zero323@users.noreply.github.com>

Closes #16771 from zero323/SPARK-19429.

1 files changed, 8 insertions, 0 deletions

diff --git a/python/pyspark/sql/tests.py b/python/pyspark/sql/tests.py
index ab9d3f6c94..d9d03337ff 100644
--- a/python/pyspark/sql/tests.py
+++ b/python/pyspark/sql/tests.py
@@ -874,6 +874,14 @@ class SQLTests(ReusedPySparkTestCase):
         self.assertTrue(all(isinstance(c, Column) for c in css))
         self.assertTrue(isinstance(ci.cast(LongType()), Column))
 
+    def test_column_getitem(self):
+        from pyspark.sql.functions import col
+
+        self.assertIsInstance(col("foo")[1:3], Column)
+        self.assertIsInstance(col("foo")[0], Column)
+        self.assertIsInstance(col("foo")["bar"], Column)
+        self.assertRaises(ValueError, lambda: col("foo")[0:10:2])
+
     def test_column_select(self):
         df = self.df
         self.assertEqual(self.testData, df.select("*").collect())