Repository: spark Updated Branches: refs/heads/master 572b62caf -> 1bd63e82f
[SPARK-7577] [ML] [DOC] add bucketizer doc CC jkbradley Author: Xusen Yin <yinxu...@gmail.com> Closes #6451 from yinxusen/SPARK-7577 and squashes the following commits: e2dc32e [Xusen Yin] rename colums e350e49 [Xusen Yin] add all demos 006ddf1 [Xusen Yin] add java test 3238481 [Xusen Yin] add bucketizer Project: http://git-wip-us.apache.org/repos/asf/spark/repo Commit: http://git-wip-us.apache.org/repos/asf/spark/commit/1bd63e82 Tree: http://git-wip-us.apache.org/repos/asf/spark/tree/1bd63e82 Diff: http://git-wip-us.apache.org/repos/asf/spark/diff/1bd63e82 Branch: refs/heads/master Commit: 1bd63e82fdb6ee57c61051430d63685b801df016 Parents: 572b62c Author: Xusen Yin <yinxu...@gmail.com> Authored: Thu May 28 17:30:12 2015 -0700 Committer: Joseph K. Bradley <jos...@databricks.com> Committed: Thu May 28 17:30:12 2015 -0700 ---------------------------------------------------------------------- docs/ml-features.md | 86 ++++++++++++++++++++ .../spark/ml/feature/JavaBucketizerSuite.java | 80 ++++++++++++++++++ 2 files changed, 166 insertions(+) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/spark/blob/1bd63e82/docs/ml-features.md ---------------------------------------------------------------------- diff --git a/docs/ml-features.md b/docs/ml-features.md index efe9b3b..d7851a5 100644 --- a/docs/ml-features.md +++ b/docs/ml-features.md @@ -789,6 +789,92 @@ scaledData = scalerModel.transform(dataFrame) </div> </div> +## Bucketizer + +`Bucketizer` transforms a column of continuous features to a column of feature buckets, where the buckets are specified by users. It takes a parameter: + +* `splits`: Parameter for mapping continuous features into buckets. With n+1 splits, there are n buckets. A bucket defined by splits x,y holds values in the range [x,y) except the last bucket, which also includes y. Splits should be strictly increasing. Values at -inf, inf must be explicitly provided to cover all Double values; Otherwise, values outside the splits specified will be treated as errors. Two examples of `splits` are `Array(Double.NegativeInfinity, 0.0, 1.0, Double.PositiveInfinity)` and `Array(0.0, 1.0, 2.0)`. + +Note that if you have no idea of the upper bound and lower bound of the targeted column, you would better add the `Double.NegativeInfinity` and `Double.PositiveInfinity` as the bounds of your splits to prevent a potenial out of Bucketizer bounds exception. + +Note also that the splits that you provided have to be in strictly increasing order, i.e. `s0 < s1 < s2 < ... < sn`. + +More details can be found in the API docs for [Bucketizer](api/scala/index.html#org.apache.spark.ml.feature.Bucketizer). + +The following example demonstrates how to bucketize a column of `Double`s into another index-wised column. + +<div class="codetabs"> +<div data-lang="scala"> +{% highlight scala %} +import org.apache.spark.ml.feature.Bucketizer +import org.apache.spark.sql.DataFrame + +val splits = Array(Double.NegativeInfinity, -0.5, 0.0, 0.5, Double.PositiveInfinity) + +val data = Array(-0.5, -0.3, 0.0, 0.2) +val dataFrame = sqlContext.createDataFrame(data.map(Tuple1.apply)).toDF("features") + +val bucketizer = new Bucketizer() + .setInputCol("features") + .setOutputCol("bucketedFeatures") + .setSplits(splits) + +// Transform original data into its bucket index. +val bucketedData = bucketizer.transform(dataFrame) +{% endhighlight %} +</div> + +<div data-lang="java"> +{% highlight java %} +import com.google.common.collect.Lists; + +import org.apache.spark.sql.DataFrame; +import org.apache.spark.sql.Row; +import org.apache.spark.sql.RowFactory; +import org.apache.spark.sql.types.DataTypes; +import org.apache.spark.sql.types.Metadata; +import org.apache.spark.sql.types.StructField; +import org.apache.spark.sql.types.StructType; + +double[] splits = {Double.NEGATIVE_INFINITY, -0.5, 0.0, 0.5, Double.POSITIVE_INFINITY}; + +JavaRDD<Row> data = jsc.parallelize(Lists.newArrayList( + RowFactory.create(-0.5), + RowFactory.create(-0.3), + RowFactory.create(0.0), + RowFactory.create(0.2) +)); +StructType schema = new StructType(new StructField[] { + new StructField("features", DataTypes.DoubleType, false, Metadata.empty()) +}); +DataFrame dataFrame = jsql.createDataFrame(data, schema); + +Bucketizer bucketizer = new Bucketizer() + .setInputCol("features") + .setOutputCol("bucketedFeatures") + .setSplits(splits); + +// Transform original data into its bucket index. +DataFrame bucketedData = bucketizer.transform(dataFrame); +{% endhighlight %} +</div> + +<div data-lang="python"> +{% highlight python %} +from pyspark.ml.feature import Bucketizer + +splits = [-float("inf"), -0.5, 0.0, 0.5, float("inf")] + +data = [(-0.5,), (-0.3,), (0.0,), (0.2,)] +dataFrame = sqlContext.createDataFrame(data, ["features"]) + +bucketizer = Bucketizer(splits=splits, inputCol="features", outputCol="bucketedFeatures") + +# Transform original data into its bucket index. +bucketedData = bucketizer.transform(dataFrame) +{% endhighlight %} +</div> +</div> # Feature Selectors http://git-wip-us.apache.org/repos/asf/spark/blob/1bd63e82/mllib/src/test/java/org/apache/spark/ml/feature/JavaBucketizerSuite.java ---------------------------------------------------------------------- diff --git a/mllib/src/test/java/org/apache/spark/ml/feature/JavaBucketizerSuite.java b/mllib/src/test/java/org/apache/spark/ml/feature/JavaBucketizerSuite.java new file mode 100644 index 0000000..d5bd230 --- /dev/null +++ b/mllib/src/test/java/org/apache/spark/ml/feature/JavaBucketizerSuite.java @@ -0,0 +1,80 @@ +/* + * 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.ml.feature; + +import com.google.common.collect.Lists; +import org.junit.After; +import org.junit.Assert; +import org.junit.Before; +import org.junit.Test; + +import org.apache.spark.api.java.JavaRDD; +import org.apache.spark.api.java.JavaSparkContext; +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.DataTypes; +import org.apache.spark.sql.types.Metadata; +import org.apache.spark.sql.types.StructField; +import org.apache.spark.sql.types.StructType; + +public class JavaBucketizerSuite { + private transient JavaSparkContext jsc; + private transient SQLContext jsql; + + @Before + public void setUp() { + jsc = new JavaSparkContext("local", "JavaBucketizerSuite"); + jsql = new SQLContext(jsc); + } + + @After + public void tearDown() { + jsc.stop(); + jsc = null; + } + + @Test + public void bucketizerTest() { + double[] splits = {-0.5, 0.0, 0.5}; + + JavaRDD<Row> data = jsc.parallelize(Lists.newArrayList( + RowFactory.create(-0.5), + RowFactory.create(-0.3), + RowFactory.create(0.0), + RowFactory.create(0.2) + )); + StructType schema = new StructType(new StructField[] { + new StructField("feature", DataTypes.DoubleType, false, Metadata.empty()) + }); + DataFrame dataset = jsql.createDataFrame(data, schema); + + Bucketizer bucketizer = new Bucketizer() + .setInputCol("feature") + .setOutputCol("result") + .setSplits(splits); + + Row[] result = bucketizer.transform(dataset).select("result").collect(); + + for (Row r : result) { + double index = r.getDouble(0); + Assert.assertTrue((index >= 0) && (index <= 1)); + } + } +} --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@spark.apache.org For additional commands, e-mail: commits-h...@spark.apache.org
