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Posted to reviews@spark.apache.org by "nchammas (via GitHub)" <gi...@apache.org> on 2023/12/14 02:09:05 UTC
Re: [PR] [SPARK-45862][PYTHON][DOCS] Add user guide for basic dataframe operations [spark]
nchammas commented on code in PR #43972:
URL: https://github.com/apache/spark/pull/43972#discussion_r1426079059
##########
python/docs/source/user_guide/basic_dataframe_operations.rst:
##########
@@ -0,0 +1,169 @@
+.. 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.
+
+==========================
+Basic DataFrame Operations
+==========================
+
+.. currentmodule:: pyspark.sql
+
+Select
+------
+
+Projects a set of expressions and returns a new :class:`DataFrame`.
+For more detailed usage methods, please refer to :meth:`DataFrame.select`.
+
+Select all columns
+~~~~~~~~~~~~~~~~~~
+
+.. code-block:: python
+
+ >>> df = spark.createDataFrame([(2, "Alice"), (5, "Bob")], schema=["age", "name"])
Review Comment:
It's not a big deal, but note that the method you used here to specify the schema is not among the methods you demonstrated [over on #43897](https://github.com/apache/spark/pull/43897/files#diff-305f8ba2839b0d1db701f7c024c1c8fe3ec6d6e338dc2ba44a1d27780a361976R44).
##########
python/docs/source/user_guide/basic_dataframe_operations.rst:
##########
@@ -0,0 +1,169 @@
+.. 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.
+
+==========================
+Basic DataFrame Operations
+==========================
+
+.. currentmodule:: pyspark.sql
+
+Select
+------
+
+Projects a set of expressions and returns a new :class:`DataFrame`.
+For more detailed usage methods, please refer to :meth:`DataFrame.select`.
+
+Select all columns
+~~~~~~~~~~~~~~~~~~
+
+.. code-block:: python
+
+ >>> df = spark.createDataFrame([(2, "Alice"), (5, "Bob")], schema=["age", "name"])
+ >>> df.select('*').show()
+ +---+-----+
+ |age| name|
+ +---+-----+
+ | 2|Alice|
+ | 5| Bob|
+ +---+-----+
+
+
+Select by column names(string) or expressions (:class:`Column`)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. code-block:: python
+
+ >>> df = spark.createDataFrame([(2, "Alice"), (5, "Bob")], schema=["age", "name"])
+ >>> df.select('name', (df.age + 10).alias('age')).show()
Review Comment:
A minor point, but should we mention or demonstrate somehow that you can also select columns using the `__getitem__` syntax (`df["age"]`) in addition to the `__getattr__` syntax (`df.age`) demonstrated here?
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