Apache Spark - A unified analytics engine for large-scale data processing
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HyukjinKwon fda0e6e48d [SPARK-29240][PYTHON] Pass Py4J column instance to support PySpark column in element_at function
### What changes were proposed in this pull request?

This PR makes `element_at` in PySpark able to take PySpark `Column` instances.

### Why are the changes needed?

To match with Scala side. Seems it was intended but not working correctly as a bug.

### Does this PR introduce any user-facing change?

Yes. See below:

```python
from pyspark.sql import functions as F
x = spark.createDataFrame([([1,2,3],1),([4,5,6],2),([7,8,9],3)],['list','num'])
x.withColumn('aa',F.element_at('list',x.num.cast('int'))).show()
```

Before:

```
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/.../spark/python/pyspark/sql/functions.py", line 2059, in element_at
    return Column(sc._jvm.functions.element_at(_to_java_column(col), extraction))
  File "/.../spark/python/lib/py4j-0.10.8.1-src.zip/py4j/java_gateway.py", line 1277, in __call__
  File "/.../spark/python/lib/py4j-0.10.8.1-src.zip/py4j/java_gateway.py", line 1241, in _build_args
  File "/.../spark/python/lib/py4j-0.10.8.1-src.zip/py4j/java_gateway.py", line 1228, in _get_args
  File "/.../forked/spark/python/lib/py4j-0.10.8.1-src.zip/py4j/java_collections.py", line 500, in convert
  File "/.../spark/python/pyspark/sql/column.py", line 344, in __iter__
    raise TypeError("Column is not iterable")
TypeError: Column is not iterable
```

After:

```
+---------+---+---+
|     list|num| aa|
+---------+---+---+
|[1, 2, 3]|  1|  1|
|[4, 5, 6]|  2|  5|
|[7, 8, 9]|  3|  9|
+---------+---+---+
```

### How was this patch tested?

Manually tested against literal, Python native types, and PySpark column.

Closes #25950 from HyukjinKwon/SPARK-29240.

Authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>
2019-09-27 11:04:55 -07:00
.github [SPARK-29199][INFRA] Add linters and license/dependency checkers to GitHub Action 2019-09-21 08:13:00 -07:00
assembly [SPARK-27300][GRAPH] Add Spark Graph modules and dependencies 2019-06-09 00:26:26 -07:00
bin [SPARK-28525][DEPLOY] Allow Launcher to be applied Java options 2019-07-30 12:45:32 -07:00
build [SPARK-29159][BUILD] Increase ReservedCodeCacheSize to 1G 2019-09-19 00:24:15 -07:00
common [SPARK-25341][CORE] Support rolling back a shuffle map stage and re-generate the shuffle files 2019-09-23 16:16:52 +08:00
conf [SPARK-29032][CORE] Add PrometheusServlet to monitor Master/Worker/Driver 2019-09-13 21:31:21 +00:00
core [SPARK-29246][CORE] Remove unnecessary imports in core module 2019-09-26 20:43:08 -07:00
data [SPARK-22666][ML][SQL] Spark datasource for image format 2018-09-05 11:59:00 -07:00
dev [SPARK-29226][BUILD] Upgrade jackson-databind to 2.9.10 and fix vulnerabilities 2019-09-24 22:05:13 -07:00
docs [SPARK-29275][SQL][DOC] Describe special date/timestamp values in the SQL migration guide 2019-09-27 10:36:20 -07:00
examples [SPARK-28980][CORE][SQL][STREAMING][MLLIB] Remove most items deprecated in Spark 2.2.0 or earlier, for Spark 3 2019-09-09 10:19:40 -05:00
external [SPARK-27748][SS][FOLLOWUP] Correct the order of logging token as debug log 2019-09-26 08:32:03 -07:00
graph [SPARK-27300][GRAPH] Add Spark Graph modules and dependencies 2019-06-09 00:26:26 -07:00
graphx [SPARK-29042][CORE] Sampling-based RDD with unordered input should be INDETERMINATE 2019-09-13 14:07:00 -07:00
hadoop-cloud [SPARK-28903][STREAMING][PYSPARK][TESTS] Fix AWS JDK version conflict that breaks Pyspark Kinesis tests 2019-08-31 10:29:46 -05:00
launcher [SPARK-29202][DEPLOY] Driver java options are not passed to driver process in Yarn client mode 2019-09-26 15:37:20 -07:00
licenses [SPARK-27557][DOC] Add copy button to Python API docs for easier copying of code-blocks 2019-05-01 11:26:18 -05:00
licenses-binary [SPARK-28772][BUILD][MLLIB] Update breeze to 1.0 2019-09-20 20:31:26 -07:00
mllib [SPARK-29258][ML][PYSPARK] parity between ml.evaluator and mllib.metrics 2019-09-27 13:30:03 +08:00
mllib-local [SPARK-29121][ML][MLLIB] Support for dot product operation on Vector(s) 2019-09-21 14:26:54 -05:00
project [SPARK-28957][SQL] Copy any "spark.hive.foo=bar" spark properties into hadoop conf as "hive.foo=bar" 2019-09-25 15:54:44 +08:00
python [SPARK-29240][PYTHON] Pass Py4J column instance to support PySpark column in element_at function 2019-09-27 11:04:55 -07:00
R [SPARK-28678][DOC] Specify that array indices start at 1 for function slice in R Scala Python 2019-09-24 18:57:54 +09:00
repl [MINOR][BUILD] Fix about 15 misc build warnings 2019-09-19 11:37:42 -07:00
resource-managers [SPARK-28937][SPARK-28936][KUBERNETES] Reduce test flakyness 2019-09-20 10:08:16 -07:00
sbin [SPARK-28164] Fix usage description of start-slave.sh 2019-06-26 12:42:33 -05:00
sql [SPARK-29015][SQL][TEST-HADOOP3.2] Reset class loader after initializing SessionState for built-in Hive 2.3 2019-09-27 10:23:56 -05:00
streaming [SPARK-23197][STREAMING][TESTS] Fix ReceiverSuite."receiver_life_cycle" to not rely on timing 2019-09-25 10:59:08 -07:00
tools [SPARK-25956] Make Scala 2.12 as default Scala version in Spark 3.0 2018-11-14 16:22:23 -08:00
.gitattributes [SPARK-3870] EOL character enforcement 2014-10-31 12:39:52 -07:00
.gitignore [SPARK-27371][CORE] Support GPU-aware resources scheduling in Standalone 2019-08-09 07:49:03 -05:00
appveyor.yml [SPARK-28759][BUILD] Upgrade scala-maven-plugin to 4.2.0 and fix build profile on AppVeyor 2019-08-30 09:39:15 -07:00
CONTRIBUTING.md [MINOR][DOCS] Tighten up some key links to the project and download pages to use HTTPS 2019-05-21 10:56:42 -07:00
LICENSE [SPARK-27557][DOC] Add copy button to Python API docs for easier copying of code-blocks 2019-05-01 11:26:18 -05:00
LICENSE-binary [SPARK-29016][BUILD] Update LICENSE and NOTICE for Hive 2.3 2019-09-23 09:19:04 -07:00
NOTICE [SPARK-23654][BUILD] remove jets3t as a dependency of spark 2018-08-16 12:34:23 -07:00
NOTICE-binary [SPARK-29016][BUILD] Update LICENSE and NOTICE for Hive 2.3 2019-09-23 09:19:04 -07:00
pom.xml [SPARK-29226][BUILD] Upgrade jackson-databind to 2.9.10 and fix vulnerabilities 2019-09-24 22:05:13 -07:00
README.md [SPARK-28473][DOC] Stylistic consistency of build command in README 2019-07-23 16:29:46 -07:00
scalastyle-config.xml [SPARK-25986][BUILD] Add rules to ban throw Errors in application code 2018-11-14 13:05:18 -08:00

Apache Spark

Spark is a unified analytics engine for large-scale data processing. It provides high-level APIs in Scala, Java, Python, and R, and an optimized engine that supports general computation graphs for data analysis. It also supports a rich set of higher-level tools including Spark SQL for SQL and DataFrames, MLlib for machine learning, GraphX for graph processing, and Structured Streaming for stream processing.

https://spark.apache.org/

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Online Documentation

You can find the latest Spark documentation, including a programming guide, on the project web page. This README file only contains basic setup instructions.

Building Spark

Spark is built using Apache Maven. To build Spark and its example programs, run:

./build/mvn -DskipTests clean package

(You do not need to do this if you downloaded a pre-built package.)

You can build Spark using more than one thread by using the -T option with Maven, see "Parallel builds in Maven 3". More detailed documentation is available from the project site, at "Building Spark".

For general development tips, including info on developing Spark using an IDE, see "Useful Developer Tools".

Interactive Scala Shell

The easiest way to start using Spark is through the Scala shell:

./bin/spark-shell

Try the following command, which should return 1,000,000,000:

scala> spark.range(1000 * 1000 * 1000).count()

Interactive Python Shell

Alternatively, if you prefer Python, you can use the Python shell:

./bin/pyspark

And run the following command, which should also return 1,000,000,000:

>>> spark.range(1000 * 1000 * 1000).count()

Example Programs

Spark also comes with several sample programs in the examples directory. To run one of them, use ./bin/run-example <class> [params]. For example:

./bin/run-example SparkPi

will run the Pi example locally.

You can set the MASTER environment variable when running examples to submit examples to a cluster. This can be a mesos:// or spark:// URL, "yarn" to run on YARN, and "local" to run locally with one thread, or "local[N]" to run locally with N threads. You can also use an abbreviated class name if the class is in the examples package. For instance:

MASTER=spark://host:7077 ./bin/run-example SparkPi

Many of the example programs print usage help if no params are given.

Running Tests

Testing first requires building Spark. Once Spark is built, tests can be run using:

./dev/run-tests

Please see the guidance on how to run tests for a module, or individual tests.

There is also a Kubernetes integration test, see resource-managers/kubernetes/integration-tests/README.md

A Note About Hadoop Versions

Spark uses the Hadoop core library to talk to HDFS and other Hadoop-supported storage systems. Because the protocols have changed in different versions of Hadoop, you must build Spark against the same version that your cluster runs.

Please refer to the build documentation at "Specifying the Hadoop Version and Enabling YARN" for detailed guidance on building for a particular distribution of Hadoop, including building for particular Hive and Hive Thriftserver distributions.

Configuration

Please refer to the Configuration Guide in the online documentation for an overview on how to configure Spark.

Contributing

Please review the Contribution to Spark guide for information on how to get started contributing to the project.