Github user liancheng commented on a diff in the pull request:
https://github.com/apache/spark/pull/14317#discussion_r71981335
--- Diff: examples/src/main/python/sql/basic.py ---
@@ -0,0 +1,194 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements. See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You 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.
+#
+
+from __future__ import print_function
+
+# $example on:init_session$
+from pyspark.sql import SparkSession
+# $example off:init_session$
+
+# $example on:schema_inferring$
+from pyspark.sql import Row
+# $example off:schema_inferring$
+
+# $example on:programmatic_schema$
+# Import data types
+from pyspark.sql.types import *
+# $example off:programmatic_schema$
+
+"""
+A simple example demonstrating basic Spark SQL features.
+Run with:
+ ./bin/spark-submit examples/src/main/python/sql/basic.py
+"""
+
+
+def basic_df_example(spark):
+ # $example on:create_df$
+ # spark is an existing SparkSession
+ df = spark.read.json("examples/src/main/resources/people.json")
+ # Displays the content of the DataFrame to stdout
+ df.show()
+ # +----+-------+
+ # | age| name|
+ # +----+-------+
+ # |null|Michael|
+ # | 30| Andy|
+ # | 19| Justin|
+ # +----+-------+
+ # $example off:create_df$
+
+ # $example on:untyped_ops$
+ # spark, df are from the previous example
+ # Print the schema in a tree format
+ df.printSchema()
+ # root
+ # |-- age: long (nullable = true)
+ # |-- name: string (nullable = true)
+
+ # Select only the "name" column
+ df.select("name").show()
+ # +-------+
+ # | name|
+ # +-------+
+ # |Michael|
+ # | Andy|
+ # | Justin|
+ # +-------+
+
+ # Select everybody, but increment the age by 1
+ df.select(df['name'], df['age'] + 1).show()
--- End diff --
Yea, I know I brought up this issue, but it is still in question...
Although `df['...']` has potential issue with self-join, it is the way Pandas
DataFrame works. Considering we've tried to workaround various self-join issues
within Catalyst, now I tend to preserve it as is. Maybe we'll deprecate this
syntax later.
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