examples/ml/JavaChiSqSelectorExample.java

0001 /*
0002  * Licensed to the Apache Software Foundation (ASF) under one or more
0003  * contributor license agreements.  See the NOTICE file distributed with
0004  * this work for additional information regarding copyright ownership.
0005  * The ASF licenses this file to You under the Apache License, Version 2.0
0006  * (the "License"); you may not use this file except in compliance with
0007  * the License.  You may obtain a copy of the License at
0008  *
0009  *    http://www.apache.org/licenses/LICENSE-2.0
0010  *
0011  * Unless required by applicable law or agreed to in writing, software
0012  * distributed under the License is distributed on an "AS IS" BASIS,
0013  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
0014  * See the License for the specific language governing permissions and
0015  * limitations under the License.
0016  */
0017
0018 package org.apache.spark.examples.ml;
0019
0020 import org.apache.spark.sql.Dataset;
0021 import org.apache.spark.sql.SparkSession;
0022
0023 // $example on$
0024 import java.util.Arrays;
0025 import java.util.List;
0026
0027 import org.apache.spark.ml.feature.ChiSqSelector;
0028 import org.apache.spark.ml.linalg.VectorUDT;
0029 import org.apache.spark.ml.linalg.Vectors;
0030 import org.apache.spark.sql.Row;
0031 import org.apache.spark.sql.RowFactory;
0032 import org.apache.spark.sql.types.DataTypes;
0033 import org.apache.spark.sql.types.Metadata;
0034 import org.apache.spark.sql.types.StructField;
0035 import org.apache.spark.sql.types.StructType;
0036 // $example off$
0037
0038 public class JavaChiSqSelectorExample {
0039   public static void main(String[] args) {
0040     SparkSession spark = SparkSession
0041       .builder()
0042       .appName("JavaChiSqSelectorExample")
0043       .getOrCreate();
0044
0045     // $example on$
0046     List<Row> data = Arrays.asList(
0047       RowFactory.create(7, Vectors.dense(0.0, 0.0, 18.0, 1.0), 1.0),
0048       RowFactory.create(8, Vectors.dense(0.0, 1.0, 12.0, 0.0), 0.0),
0049       RowFactory.create(9, Vectors.dense(1.0, 0.0, 15.0, 0.1), 0.0)
0050     );
0051     StructType schema = new StructType(new StructField[]{
0052       new StructField("id", DataTypes.IntegerType, false, Metadata.empty()),
0053       new StructField("features", new VectorUDT(), false, Metadata.empty()),
0054       new StructField("clicked", DataTypes.DoubleType, false, Metadata.empty())
0055     });
0056
0057     Dataset<Row> df = spark.createDataFrame(data, schema);
0058
0059     ChiSqSelector selector = new ChiSqSelector()
0060       .setNumTopFeatures(1)
0061       .setFeaturesCol("features")
0062       .setLabelCol("clicked")
0063       .setOutputCol("selectedFeatures");
0064
0065     Dataset<Row> result = selector.fit(df).transform(df);
0066
0067     System.out.println("ChiSqSelector output with top " + selector.getNumTopFeatures()
0068         + " features selected");
0069     result.show();
0070
0071     // $example off$
0072     spark.stop();
0073   }
0074 }