Apache Spark - A unified analytics engine for large-scale data processing
Go to file
Liang-Chi Hsieh d21aab403a
[SPARK-30941][PYSPARK] Add a note to asDict to document its behavior when there are duplicate fields
### What changes were proposed in this pull request?

Adding a note to document `Row.asDict` behavior when there are duplicate fields.

### Why are the changes needed?

When a row contains duplicate fields, `asDict` and `_get_item_` behaves differently. We should document it to let users know the difference explicitly.

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

No. Only document change.

### How was this patch tested?

Existing test.

Closes #27853 from viirya/SPARK-30941.

Authored-by: Liang-Chi Hsieh <viirya@gmail.com>
Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>
2020-03-09 11:06:45 -07:00
.github [SPARK-30963][INFRA] Add GitHub Action job for document generation 2020-02-26 19:24:41 -08:00
assembly [SPARK-30950][BUILD] Setting version to 3.1.0-SNAPSHOT 2020-02-25 19:44:31 -08:00
bin [SPARK-30884][PYSPARK] Upgrade to Py4J 0.10.9 2020-02-20 09:09:30 -08:00
build [SPARK-30121][BUILD] Fix memory usage in sbt build script 2019-12-05 11:50:55 -06:00
common [SPARK-31014][CORE] InMemoryStore: remove key from parentToChildrenMap when removing key from CountingRemoveIfForEach 2020-03-04 10:05:26 -08:00
conf [SPARK-29032][CORE] Add PrometheusServlet to monitor Master/Worker/Driver 2019-09-13 21:31:21 +00:00
core [SPARK-31082][CORE] MapOutputTrackerMaster.getMapLocation should handle last mapIndex correctly 2020-03-09 15:53:34 +08:00
data [SPARK-22666][ML][SQL] Spark datasource for image format 2018-09-05 11:59:00 -07:00
dev [SPARK-30879][DOCS] Refine workflow for building docs 2020-03-07 11:43:32 -06:00
docs [SPARK-31002][CORE][DOC] Add version information to the configuration of Core 2020-03-08 12:31:57 +09:00
examples [SPARK-30950][BUILD] Setting version to 3.1.0-SNAPSHOT 2020-02-25 19:44:31 -08:00
external [SPARK-31050][TEST] Disable flaky Roundtrip test in KafkaDelegationTokenSuite 2020-03-05 00:21:32 -08:00
graphx [SPARK-30950][BUILD] Setting version to 3.1.0-SNAPSHOT 2020-02-25 19:44:31 -08:00
hadoop-cloud [SPARK-30950][BUILD] Setting version to 3.1.0-SNAPSHOT 2020-02-25 19:44:31 -08:00
launcher [SPARK-30950][BUILD] Setting version to 3.1.0-SNAPSHOT 2020-02-25 19:44:31 -08:00
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-29308][BUILD] Update deps in dev/deps/spark-deps-hadoop-3.2 for hadoop-3.2 2019-10-13 12:53:12 -05:00
mllib [SPARK-30929][ML] ML, GraphX 3.0 QA: API: New Scala APIs, docs 2020-03-09 09:11:21 -05:00
mllib-local [SPARK-30770][ML] avoid vector conversion in GMM.transform 2020-03-04 11:02:27 +08:00
project [SPARK-30994][BUILD][FOLLOW-UP] Change scope of xml-apis to include it and add xerces in SBT as dependency override 2020-03-06 09:39:02 +09:00
python [SPARK-30941][PYSPARK] Add a note to asDict to document its behavior when there are duplicate fields 2020-03-09 11:06:45 -07:00
R [SPARK-30682][SPARKR][SQL] Add SparkR interface for higher order functions 2020-02-28 12:58:56 +09:00
repl [SPARK-30950][BUILD] Setting version to 3.1.0-SNAPSHOT 2020-02-25 19:44:31 -08:00
resource-managers [SPARK-29149][YARN] Update YARN cluster manager For Stage Level Scheduling 2020-02-28 15:23:33 -06:00
sbin [SPARK-30884][PYSPARK] Upgrade to Py4J 0.10.9 2020-02-20 09:09:30 -08:00
sql [SPARK-31082][CORE] MapOutputTrackerMaster.getMapLocation should handle last mapIndex correctly 2020-03-09 15:53:34 +08:00
streaming [SPARK-30950][BUILD] Setting version to 3.1.0-SNAPSHOT 2020-02-25 19:44:31 -08:00
tools [SPARK-30950][BUILD] Setting version to 3.1.0-SNAPSHOT 2020-02-25 19:44:31 -08:00
.gitattributes [SPARK-30653][INFRA][SQL] EOL character enforcement for java/scala/xml/py/R files 2020-01-27 10:20:51 -08:00
.gitignore [SPARK-30879][DOCS] Refine workflow for building docs 2020-03-07 11:43:32 -06:00
appveyor.yml [SPARK-23435][INFRA][FOLLOW-UP] Remove unnecessary dependency in AppVeyor 2020-02-27 00:18:46 -08:00
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-29674][CORE] Update dropwizard metrics to 4.1.x for JDK 9+ 2019-11-03 15:13:06 -08:00
LICENSE-binary [SPARK-30695][BUILD] Upgrade Apache ORC to 1.5.9 2020-01-31 17:41:27 -08:00
NOTICE [SPARK-29674][CORE] Update dropwizard metrics to 4.1.x for JDK 9+ 2019-11-03 15:13:06 -08:00
NOTICE-binary [SPARK-29674][CORE] Update dropwizard metrics to 4.1.x for JDK 9+ 2019-11-03 15:13:06 -08:00
pom.xml [SPARK-30994][BUILD][FOLLOW-UP] Change scope of xml-apis to include it and add xerces in SBT as dependency override 2020-03-06 09:39:02 +09:00
README.md [MINOR][DOCS] Fix Jenkins build image and link in README.md 2020-01-20 23:08:24 -08:00
scalastyle-config.xml [SPARK-30030][INFRA] Use RegexChecker instead of TokenChecker to check org.apache.commons.lang. 2019-11-25 12:03:15 -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/

Jenkins Build AppVeyor Build PySpark Coverage

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.)

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.