Apache Spark - A unified analytics engine for large-scale data processing
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Shashwat Anand 4aaa7d40bf [MINOR][DOC] Use raw triple double quotes around docstrings where there are occurrences of backslashes.
From [PEP 257](https://www.python.org/dev/peps/pep-0257/):

> For consistency, always use """triple double quotes""" around docstrings. Use r"""raw triple double quotes""" if you use any backslashes in your docstrings. For Unicode docstrings, use u"""Unicode triple-quoted strings""".

For example, this is what help (kafka_wordcount) shows:

```
DESCRIPTION
    Counts words in UTF8 encoded, '
    ' delimited text received from the network every second.
     Usage: kafka_wordcount.py <zk> <topic>

     To run this on your local machine, you need to setup Kafka and create a producer first, see
     http://kafka.apache.org/documentation.html#quickstart

     and then run the example
        `$ bin/spark-submit --jars       external/kafka-assembly/target/scala-*/spark-streaming-kafka-assembly-*.jar       examples/src/main/python/streaming/kafka_wordcount.py       localhost:2181 test`
```

This is what it shows, after the fix:

```
DESCRIPTION
    Counts words in UTF8 encoded, '\n' delimited text received from the network every second.
    Usage: kafka_wordcount.py <zk> <topic>

    To run this on your local machine, you need to setup Kafka and create a producer first, see
    http://kafka.apache.org/documentation.html#quickstart

    and then run the example
       `$ bin/spark-submit --jars \
         external/kafka-assembly/target/scala-*/spark-streaming-kafka-assembly-*.jar \
         examples/src/main/python/streaming/kafka_wordcount.py \
         localhost:2181 test`
```

The thing worth noticing is no linebreak here in the help.

## What changes were proposed in this pull request?

Change triple double quotes to raw triple double quotes when there are occurrences of backslashes in docstrings.

## How was this patch tested?

Manually as this is a doc fix.

Author: Shashwat Anand <me@shashwat.me>

Closes #20497 from ashashwat/docstring-fixes.
2018-02-03 10:31:04 -08:00
.github [SPARK-18073][DOCS][WIP] Migrate wiki to spark.apache.org web site 2016-11-23 11:25:47 +00:00
assembly [SPARK-23028] Bump master branch version to 2.4.0-SNAPSHOT 2018-01-13 00:37:59 +08:00
bin [SPARK-22994][K8S] Use a single image for all Spark containers. 2018-01-11 10:37:35 -08:00
build [SPARK-19810][BUILD][CORE] Remove support for Scala 2.10 2017-07-13 17:06:24 +08:00
common [SPARK-23289][CORE] OneForOneBlockFetcher.DownloadCallback.onData should write the buffer fully 2018-02-01 21:00:47 +08:00
conf [SPARK-22466][SPARK SUBMIT] export SPARK_CONF_DIR while conf is default 2017-11-09 14:33:08 +09:00
core [SPARK-23253][CORE][SHUFFLE] Only write shuffle temporary index file when there is not an existing one 2018-02-02 09:10:50 -06:00
data [SPARK-23205][ML] Update ImageSchema.readImages to correctly set alpha values for four-channel images 2018-01-25 18:15:29 -06:00
dev [SPARK-23295][BUILD][MINOR] Exclude Waring message when generating versions in make-distribution.sh 2018-02-02 10:17:51 -06:00
docs [SPARK-23064][SS][DOCS] Stream-stream joins Documentation - follow up 2018-02-02 17:37:51 -08:00
examples [MINOR][DOC] Use raw triple double quotes around docstrings where there are occurrences of backslashes. 2018-02-03 10:31:04 -08:00
external [SPARK-23317][SQL] rename ContinuousReader.setOffset to setStartOffset 2018-02-02 20:49:08 -08:00
graphx [SPARK-23028] Bump master branch version to 2.4.0-SNAPSHOT 2018-01-13 00:37:59 +08:00
hadoop-cloud [SPARK-23028] Bump master branch version to 2.4.0-SNAPSHOT 2018-01-13 00:37:59 +08:00
launcher [SPARK-23020][CORE] Fix another race in the in-process launcher test. 2018-02-02 11:43:22 +08:00
licenses [SPARK-19112][CORE] Support for ZStandard codec 2017-11-01 14:54:08 +01:00
mllib [SPARK-23107][ML] ML 2.3 QA: New Scala APIs, docs. 2018-02-01 11:25:01 +02:00
mllib-local [SPARK-23085][ML] API parity for mllib.linalg.Vectors.sparse 2018-01-19 09:28:35 -06:00
project [SPARK-23070] Bump previousSparkVersion in MimaBuild.scala to be 2.2.0 2018-01-15 22:32:38 +08:00
python [SPARK-22274][PYTHON][SQL][FOLLOWUP] Use assertRaisesRegexp instead of assertRaisesRegex. 2018-01-31 22:26:27 -08:00
R [SPARK-23157][SQL][FOLLOW-UP] DataFrame -> SparkDataFrame in R comment 2018-02-01 11:15:17 +09:00
repl [SPARK-23028] Bump master branch version to 2.4.0-SNAPSHOT 2018-01-13 00:37:59 +08:00
resource-managers [SPARK-23296][YARN] Include stacktrace in YARN-app diagnostic 2018-02-01 15:26:59 -08:00
sbin [SPARK-22994][K8S] Use a single image for all Spark containers. 2018-01-11 10:37:35 -08:00
sql [SPARK-23305][SQL][TEST] Test spark.sql.files.ignoreMissingFiles for all file-based data sources 2018-02-03 00:04:00 -08:00
streaming Revert "[SPARK-23200] Reset Kubernetes-specific config on Checkpoint restore" 2018-02-01 14:00:08 +08:00
tools [SPARK-23028] Bump master branch version to 2.4.0-SNAPSHOT 2018-01-13 00:37:59 +08:00
.gitattributes [SPARK-3870] EOL character enforcement 2014-10-31 12:39:52 -07:00
.gitignore [SPARK-7721][PYTHON][TESTS] Adds PySpark coverage generation script 2018-01-22 22:12:50 +09:00
.travis.yml [SPARK-18278][SCHEDULER] Spark on Kubernetes - Basic Scheduler Backend 2017-11-28 23:02:09 -08:00
appveyor.yml [SPARK-22817][R] Use fixed testthat version for SparkR tests in AppVeyor 2017-12-17 14:40:41 +09:00
CONTRIBUTING.md [SPARK-18073][DOCS][WIP] Migrate wiki to spark.apache.org web site 2016-11-23 11:25:47 +00:00
LICENSE [SPARK-19112][CORE] Support for ZStandard codec 2017-11-01 14:54:08 +01:00
NOTICE [SPARK-18278][SCHEDULER] Spark on Kubernetes - Basic Scheduler Backend 2017-11-28 23:02:09 -08:00
pom.xml [SPARK-23043][BUILD] Upgrade json4s to 3.5.3 2018-01-13 09:40:00 -06:00
README.md [MINOR][DOCS] Replace non-breaking space to normal spaces that breaks rendering markdown 2017-04-03 10:09:11 +01:00
scalastyle-config.xml [SPARK-20657][CORE] Speed up rendering of the stages page. 2018-01-11 19:41:48 +08:00

Apache Spark

Spark is a fast and general cluster computing system for Big Data. 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 Spark Streaming for stream processing.

http://spark.apache.org/

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 1000:

scala> sc.parallelize(1 to 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 1000:

>>> sc.parallelize(range(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.

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" 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.