sparkML原始数据转换成label-features方法

数据1:kaggle-旧金山犯罪分类数据
格式如下:
Dates,Category,Descript,DayOfWeek,PdDistrict,Resolution,Address,X,Y
2015-05-13 23:53:00,WARRANTS,WARRANT ARREST,Wednesday,NORTHERN,"ARREST, BOOKED",OAK ST / LAGUNA ST,-122.425891675136,37.7745985956747
2015-05-13 23:53:00,OTHER OFFENSES,TRAFFIC VIOLATION ARREST,Wednesday,NORTHERN,"ARREST, BOOKED",OAK ST / LAGUNA ST,-122.425891675136,37.7745985956747
2015-05-13 23:33:00,OTHER OFFENSES,TRAFFIC VIOLATION ARREST,Wednesday,NORTHERN,"ARREST, BOOKED",VANNESS AV / GREENWICH ST,-122.42436302145,37.8004143219856
2015-05-13 23:30:00,LARCENY/THEFT,GRAND THEFT FROM LOCKED AUTO,Wednesday,NORTHERN,NONE,1500 Block of LOMBARD ST,-122.42699532676599,37.80087263276921
2015-05-13 23:30:00,LARCENY/THEFT,GRAND THEFT FROM LOCKED AUTO,Wednesday,PARK,NONE,100 Block of BRODERICK ST,-122.438737622757,37.771541172057795
2015-05-13 23:30:00,LARCENY/THEFT,GRAND THEFT FROM UNLOCKED AUTO,Wednesday,INGLESIDE,NONE,0 Block of TEDDY AV,-122.40325236121201,37.713430704116
2015-05-13 23:30:00,VEHICLE THEFT,STOLEN AUTOMOBILE,Wednesday,INGLESIDE,NONE,AVALON AV / PERU AV,-122.423326976668,37.7251380403778
2015-05-13 23:30:00,VEHICLE THEFT,STOLEN AUTOMOBILE,Wednesday,BAYVIEW,NONE,KIRKWOOD AV / DONAHUE ST,-122.371274317441,37.7275640719518
2015-05-13 23:00:00,LARCENY/THEFT,GRAND THEFT FROM LOCKED AUTO,Wednesday,RICHMOND,NONE,600 Block of 47TH AV,-122.508194031117,37.776601260681204

测试代码:

    public static void main(String[] args) {

        SparkSession spark = SparkSession.builder().enableHiveSupport()
                .getOrCreate();
        Dataset<Row> dataset = spark
                .read()
                .format("org.apache.spark.sql.execution.datasources.csv.CSVFileFormat")
                .option("header", true)
                .option("inferSchema", true)
                .option("delimiter", ",")
                .load("file:///E:/git/bigdata_sparkIDE/spark-ide/workspace/test/SparkMLTest/SanFranciscoCrime/document/kaggle-旧金山犯罪分类/train-new.csv")
                .persist();

        DataPreProcess(dataset);

    }

   //此函数包含StringIndexer,OneHotEncoder,VectorAssembler,VectorIndexer数据转换方法
    public static Dataset<Row> DataPreProcess(Dataset<Row> data) {

        //Dataset<Row> df = data.selectExpr("cast(Dates as String) ,DayOfWeek,PdDistrict,Category".split(","));

        Dataset<Row> df = data.select(data.col("Dates").cast("String").alias("Dates"),data.col("DayOfWeek").alias("DayOfWeek"),data.col("PdDistrict"),data.col("Category"));
        df.printSchema();
        // 重新索引标签值

        SparkLog.info(data.select("Category").distinct().count());

        //将非数字类型标签转换成数字类型,按照标签去重的个数n,编号0~n,相同标签的多行记录转换后的数字标签编号相同
        //这个适合所有非数字且不连续的有限类别数据编号,不仅仅是只能编号标签
        StringIndexerModel labelIndexer = new StringIndexer()
                .setInputCol("Category").setOutputCol("label").fit(df);

        StringIndexerModel DateIndexer = new StringIndexer()
                .setInputCol("Dates").setOutputCol("DatesNum").fit(df);

        StringIndexerModel DayOfWeekIndexer = new StringIndexer()
                .setInputCol("DayOfWeek").setOutputCol("dfNum").fit(df);

        StringIndexerModel PdDistrictIndexer = new StringIndexer()
                .setInputCol("PdDistrict").setOutputCol("pdNum").fit(df);

        /*独热编码将类别特征(离散的,已经转换为数字编号形式(这个是必须的,否则会报错),
        映射成独热编码,生成的是一个稀疏向量
        比如字符串"abcab"的映射规则:去重后的特征个数n即为稀疏向量的维数,而数字编号代
        表该特征对应的向量中非0值的下标,最后生成0-1编码的向量
        a  1 0 0
        b  0 1 0
        c  0 0 1
        a  1 0 0
        b  0 1 0
        */
        
        //OneHotEncoder不需要fit
        OneHotEncoder encoder = new OneHotEncoder().setInputCol("dfNum")
                .setOutputCol("dfvec")
                .setDropLast(false);  // 设置最后一个是否包含

        OneHotEncoder encoder1 = new OneHotEncoder().setInputCol("pdNum")
                .setOutputCol("pdvec")
                .setDropLast(false);// 设置最后一个是否包含

        OneHotEncoder encoder2 = new OneHotEncoder().setInputCol("DatesNum")
                .setOutputCol("Datesvec")
                .setDropLast(false);// 设置最后一个是否包含

        //将多个列拼接成一个向量,列的类型可以是向量
        VectorAssembler assembler = new VectorAssembler().setInputCols(
                "Datesvec,dfvec,pdvec".split(",")).setOutputCol("features");

        // Dataset<Row> assembledFeatures = assembler.transform(df);

        Pipeline pipeline = new Pipeline().setStages(new PipelineStage[] {
                DateIndexer, DayOfWeekIndexer, PdDistrictIndexer, encoder,
                encoder1, encoder2, labelIndexer, assembler });

        // Train model. This also runs the indexers.
        PipelineModel model = pipeline.fit(df);

        // Make predictions.
        Dataset<Row> predictions = model.transform(df);
        predictions.describe("label").show();
        predictions.show(100, false);
        
        return predictions;

    }

+-------------------+---------+----------+--------------+--------+-----+-----+-------------+--------------+-----------------------+-----+---------------------------------------------+
|Dates |DayOfWeek|PdDistrict|Category |DatesNum|dfNum|pdNum|dfvec |pdvec |Datesvec |label|features |
+-------------------+---------+----------+--------------+--------+-----+-----+-------------+--------------+-----------------------+-----+---------------------------------------------+
|2015-05-13 23:53:00|Wednesday|NORTHERN |WARRANTS |172231.0|1.0 |2.0 |(7,[1],[1.0])|(10,[2],[1.0])|(389257,[172231],[1.0])|7.0 |(389274,[172231,389258,389266],[1.0,1.0,1.0])|
|2015-05-13 23:53:00|Wednesday|NORTHERN |OTHER OFFENSES|172231.0|1.0 |2.0 |(7,[1],[1.0])|(10,[2],[1.0])|(389257,[172231],[1.0])|1.0 |(389274,[172231,389258,389266],[1.0,1.0,1.0])|
|2015-05-13 18:05:00|Wednesday|BAYVIEW |LARCENY/THEFT |330092.0|1.0 |3.0 |(7,[1],[1.0])|(10,[3],[1.0])|(389257,[330092],[1.0])|0.0 |(389274,[330092,389258,389267],[1.0,1.0,1.0])|
|2015-05-13 18:02:00|Wednesday|MISSION |OTHER OFFENSES|387792.0|1.0 |1.0 |(7,[1],[1.0])|(10,[1],[1.0])|(389257,[387792],[1.0])|1.0 |(389274,[387792,389258,389265],[1.0,1.0,1.0])|
|2015-05-13 18:00:00|Wednesday|SOUTHERN |BURGLARY |32607.0 |1.0 |0.0 |(7,[1],[1.0])|(10,[0],[1.0])|(389257,[32607],[1.0]) |8.0 |(389274,[32607,389258,389264],[1.0,1.0,1.0]) |
|2015-05-13 18:00:00|Wednesday|BAYVIEW |LARCENY/THEFT |32607.0 |1.0 |3.0 |(7,[1],[1.0])|(10,[3],[1.0])|(389257,[32607],[1.0]) |0.0 |(389274,[32607,389258,389267],[1.0,1.0,1.0]) |
|2015-05-13 18:00:00|Wednesday|PARK |LARCENY/THEFT |32607.0 |1.0 |8.0 |(7,[1],[1.0])|(10,[8],[1.0])|(389257,[32607],[1.0]) |0.0 |(389274,[32607,389258,389272],[1.0,1.0,1.0]) |
+-------------------+---------+----------+--------------+--------+-----+-----+-------------+--------------+-----------------------+-----+---------------------------------------------+
only showing top 7 rows
*******************************************************************************************************************

数据2:

id,name,age,sex,rate
1,lyy,20,F,0.6
2,rdd,20,M,0.4
3,nyc,18,M,0.55
4,mzy,10,M,0.21
1 //Binarizer二值化: 将该列数据二值化,大于阈值的为1.0,否则为0.0  spark源码:udf { in: Double => if (in > td) 1.0 else 0.0 }
2 
3 Dataset<Row> result = new Binarizer()
4                 .setInputCol("rate")
5                 .setOutputCol("flag")
6                 .setThreshold(0.5).transform(data);
7                 
8                 result.show(10, false);
+---+----+---+---+----+----+
|id |name|age|sex|rate|flag|
+---+----+---+---+----+----+
|1 |lyy |20 |F |0.6 |1.0 |
|2 |rdd |20 |M |0.4 |0.0 |
|3 |nyc |18 |M |0.55|1.0 |
|4 |mzy |10 |M |0.21|0.0 |
+---+----+---+---+----+----+
 1 //IndexToString将stringindexder转换的数据转回到原始的数据
 2 
 3  StringIndexer labelIndexer = new StringIndexer()
 4                  .setInputCol("sex")
 5                  .setOutputCol("label");
 6                  
 7                  IndexToString IndexToSex = new  IndexToString()
 8                              .setInputCol("label")
 9                              .setOutputCol("orisex");
10                  
11                  Pipeline pipeline = new Pipeline().setStages(new PipelineStage[] {    labelIndexer,    IndexToSex});
12                  PipelineModel model = pipeline.fit(data);
13  
14                  // Make predictions.
15                  Dataset<Row> result = model.transform(data);
16                  
17                  result.show(10, false);

 

 1                 //Bucketizer 分箱(分段处理):将连续数值转换为离散类别
 2                 //比如特征是年龄,是一个连续数值,需要将其转换为离散类别(未成年人、青年人、中年人、老年人),就要用到Bucketizer了
 3                 //如age > 55 老年人
 4                 double[] splits={0,18,35,55,Double.POSITIVE_INFINITY};//[0,18),[18,35),[35,55),[55,正无穷)
 5                 Dataset<Row> result=new Bucketizer()
 6                  .setInputCol("age")
 7                  .setOutputCol("bucketCategory")
 8                  .setSplits(splits)//设置分段标准
 9                  .transform(data);
10 
11                 result.show(10, false);



原文地址:https://www.cnblogs.com/lyy-blog/p/9518177.html