diff options
author | Yanbo Liang <ybliang8@gmail.com> | 2015-12-07 23:50:57 -0800 |
---|---|---|
committer | Xiangrui Meng <meng@databricks.com> | 2015-12-07 23:50:57 -0800 |
commit | 4a39b5a1bee28cec792d509654f6236390cafdcb (patch) | |
tree | 1637657b13ee5294d74abf8f3f2f4c3f5bf9ba86 | |
parent | 7d05a624510f7299b3dd07f87c203db1ff7caa3e (diff) | |
download | spark-4a39b5a1bee28cec792d509654f6236390cafdcb.tar.gz spark-4a39b5a1bee28cec792d509654f6236390cafdcb.tar.bz2 spark-4a39b5a1bee28cec792d509654f6236390cafdcb.zip |
[SPARK-11958][SPARK-11957][ML][DOC] SQLTransformer user guide and example code
Add ```SQLTransformer``` user guide, example code and make Scala API doc more clear.
Author: Yanbo Liang <ybliang8@gmail.com>
Closes #10006 from yanboliang/spark-11958.
5 files changed, 212 insertions, 2 deletions
diff --git a/docs/ml-features.md b/docs/ml-features.md index 5105a948fe..f85e0d56d2 100644 --- a/docs/ml-features.md +++ b/docs/ml-features.md @@ -756,6 +756,65 @@ for more details on the API. </div> </div> +## SQLTransformer + +`SQLTransformer` implements the transformations which are defined by SQL statement. +Currently we only support SQL syntax like `"SELECT ... FROM __THIS__ ..."` +where `"__THIS__"` represents the underlying table of the input dataset. +The select clause specifies the fields, constants, and expressions to display in +the output, it can be any select clause that Spark SQL supports. Users can also +use Spark SQL built-in function and UDFs to operate on these selected columns. +For example, `SQLTransformer` supports statements like: + +* `SELECT a, a + b AS a_b FROM __THIS__` +* `SELECT a, SQRT(b) AS b_sqrt FROM __THIS__ where a > 5` +* `SELECT a, b, SUM(c) AS c_sum FROM __THIS__ GROUP BY a, b` + +**Examples** + +Assume that we have the following DataFrame with columns `id`, `v1` and `v2`: + +~~~~ + id | v1 | v2 +----|-----|----- + 0 | 1.0 | 3.0 + 2 | 2.0 | 5.0 +~~~~ + +This is the output of the `SQLTransformer` with statement `"SELECT *, (v1 + v2) AS v3, (v1 * v2) AS v4 FROM __THIS__"`: + +~~~~ + id | v1 | v2 | v3 | v4 +----|-----|-----|-----|----- + 0 | 1.0 | 3.0 | 4.0 | 3.0 + 2 | 2.0 | 5.0 | 7.0 |10.0 +~~~~ + +<div class="codetabs"> +<div data-lang="scala" markdown="1"> + +Refer to the [SQLTransformer Scala docs](api/scala/index.html#org.apache.spark.ml.feature.SQLTransformer) +for more details on the API. + +{% include_example scala/org/apache/spark/examples/ml/SQLTransformerExample.scala %} +</div> + +<div data-lang="java" markdown="1"> + +Refer to the [SQLTransformer Java docs](api/java/org/apache/spark/ml/feature/SQLTransformer.html) +for more details on the API. + +{% include_example java/org/apache/spark/examples/ml/JavaSQLTransformerExample.java %} +</div> + +<div data-lang="python" markdown="1"> + +Refer to the [SQLTransformer Python docs](api/python/pyspark.ml.html#pyspark.ml.feature.SQLTransformer) for more details on the API. + +{% include_example python/ml/sql_transformer.py %} +</div> +</div> + ## VectorAssembler `VectorAssembler` is a transformer that combines a given list of columns into a single vector diff --git a/examples/src/main/java/org/apache/spark/examples/ml/JavaSQLTransformerExample.java b/examples/src/main/java/org/apache/spark/examples/ml/JavaSQLTransformerExample.java new file mode 100644 index 0000000000..d55c70796a --- /dev/null +++ b/examples/src/main/java/org/apache/spark/examples/ml/JavaSQLTransformerExample.java @@ -0,0 +1,59 @@ +/* + * 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. + */ + +package org.apache.spark.examples.ml; + +// $example on$ +import java.util.Arrays; + +import org.apache.spark.SparkConf; +import org.apache.spark.api.java.JavaRDD; +import org.apache.spark.api.java.JavaSparkContext; +import org.apache.spark.ml.feature.SQLTransformer; +import org.apache.spark.sql.DataFrame; +import org.apache.spark.sql.Row; +import org.apache.spark.sql.RowFactory; +import org.apache.spark.sql.SQLContext; +import org.apache.spark.sql.types.*; +// $example off$ + +public class JavaSQLTransformerExample { + public static void main(String[] args) { + + SparkConf conf = new SparkConf().setAppName("JavaSQLTransformerExample"); + JavaSparkContext jsc = new JavaSparkContext(conf); + SQLContext sqlContext = new SQLContext(jsc); + + // $example on$ + JavaRDD<Row> jrdd = jsc.parallelize(Arrays.asList( + RowFactory.create(0, 1.0, 3.0), + RowFactory.create(2, 2.0, 5.0) + )); + StructType schema = new StructType(new StructField [] { + new StructField("id", DataTypes.IntegerType, false, Metadata.empty()), + new StructField("v1", DataTypes.DoubleType, false, Metadata.empty()), + new StructField("v2", DataTypes.DoubleType, false, Metadata.empty()) + }); + DataFrame df = sqlContext.createDataFrame(jrdd, schema); + + SQLTransformer sqlTrans = new SQLTransformer().setStatement( + "SELECT *, (v1 + v2) AS v3, (v1 * v2) AS v4 FROM __THIS__"); + + sqlTrans.transform(df).show(); + // $example off$ + } +} diff --git a/examples/src/main/python/ml/sql_transformer.py b/examples/src/main/python/ml/sql_transformer.py new file mode 100644 index 0000000000..9575d728d8 --- /dev/null +++ b/examples/src/main/python/ml/sql_transformer.py @@ -0,0 +1,40 @@ +# +# 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 + +from pyspark import SparkContext +# $example on$ +from pyspark.ml.feature import SQLTransformer +# $example off$ +from pyspark.sql import SQLContext + +if __name__ == "__main__": + sc = SparkContext(appName="SQLTransformerExample") + sqlContext = SQLContext(sc) + + # $example on$ + df = sqlContext.createDataFrame([ + (0, 1.0, 3.0), + (2, 2.0, 5.0) + ], ["id", "v1", "v2"]) + sqlTrans = SQLTransformer( + statement="SELECT *, (v1 + v2) AS v3, (v1 * v2) AS v4 FROM __THIS__") + sqlTrans.transform(df).show() + # $example off$ + + sc.stop() diff --git a/examples/src/main/scala/org/apache/spark/examples/ml/SQLTransformerExample.scala b/examples/src/main/scala/org/apache/spark/examples/ml/SQLTransformerExample.scala new file mode 100644 index 0000000000..014abd1fdb --- /dev/null +++ b/examples/src/main/scala/org/apache/spark/examples/ml/SQLTransformerExample.scala @@ -0,0 +1,45 @@ +/* + * 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. + */ + +// scalastyle:off println +package org.apache.spark.examples.ml + +// $example on$ +import org.apache.spark.ml.feature.SQLTransformer +// $example off$ +import org.apache.spark.sql.SQLContext +import org.apache.spark.{SparkConf, SparkContext} + + +object SQLTransformerExample { + def main(args: Array[String]) { + val conf = new SparkConf().setAppName("SQLTransformerExample") + val sc = new SparkContext(conf) + val sqlContext = new SQLContext(sc) + + // $example on$ + val df = sqlContext.createDataFrame( + Seq((0, 1.0, 3.0), (2, 2.0, 5.0))).toDF("id", "v1", "v2") + + val sqlTrans = new SQLTransformer().setStatement( + "SELECT *, (v1 + v2) AS v3, (v1 * v2) AS v4 FROM __THIS__") + + sqlTrans.transform(df).show() + // $example off$ + } +} +// scalastyle:on println diff --git a/mllib/src/main/scala/org/apache/spark/ml/feature/SQLTransformer.scala b/mllib/src/main/scala/org/apache/spark/ml/feature/SQLTransformer.scala index 3a735017ba..c09f4d076c 100644 --- a/mllib/src/main/scala/org/apache/spark/ml/feature/SQLTransformer.scala +++ b/mllib/src/main/scala/org/apache/spark/ml/feature/SQLTransformer.scala @@ -27,9 +27,16 @@ import org.apache.spark.sql.types.StructType /** * :: Experimental :: - * Implements the transforms which are defined by SQL statement. - * Currently we only support SQL syntax like 'SELECT ... FROM __THIS__' + * Implements the transformations which are defined by SQL statement. + * Currently we only support SQL syntax like 'SELECT ... FROM __THIS__ ...' * where '__THIS__' represents the underlying table of the input dataset. + * The select clause specifies the fields, constants, and expressions to display in + * the output, it can be any select clause that Spark SQL supports. Users can also + * use Spark SQL built-in function and UDFs to operate on these selected columns. + * For example, [[SQLTransformer]] supports statements like: + * - SELECT a, a + b AS a_b FROM __THIS__ + * - SELECT a, SQRT(b) AS b_sqrt FROM __THIS__ where a > 5 + * - SELECT a, b, SUM(c) AS c_sum FROM __THIS__ GROUP BY a, b */ @Experimental @Since("1.6.0") |