固定条数分层随机采样 (StratifiedSampleWithSizeBatchOp)

Java 类名：com.alibaba.alink.operator.batch.dataproc.StratifiedSampleWithSizeBatchOp
Python 类名：StratifiedSampleWithSizeBatchOp

功能介绍

本算子对输入数据的每个类别进行指定个数的分层随机抽样。

参数说明

代码示例

Python 代码

from pyalink.alink import *
import pandas as pd
useLocalEnv(1)
df = pd.DataFrame([
        ['a',0.0,0.0],
        ['a',0.2,0.1],
        ['b',0.2,0.8],
        ['b',9.5,9.7],
        ['b',9.1,9.6],
        ['b',9.3,9.9]
    ])
batchData = BatchOperator.fromDataframe(df, schemaStr='x1 string, x2 double, x3 double')
sampleOp = StratifiedSampleWithSizeBatchOp() \
       .setStrataCol("x1") \
       .setStrataSizes("a:1,b:2")
batchData.link(sampleOp).print()

Java 代码

import org.apache.flink.types.Row;
import com.alibaba.alink.operator.batch.BatchOperator;
import com.alibaba.alink.operator.batch.dataproc.StratifiedSampleWithSizeBatchOp;
import com.alibaba.alink.operator.batch.source.MemSourceBatchOp;
import org.junit.Test;
import java.util.Arrays;
import java.util.List;
public class StratifiedSampleWithSizeBatchOpTest {
    @Test
    public void testStratifiedSampleWithSizeBatchOp() throws Exception {
        List <Row> df = Arrays.asList(
            Row.of("a", 0.0, 0.0),
            Row.of("a", 0.2, 0.1),
            Row.of("b", 0.2, 0.8),
            Row.of("b", 9.5, 9.7),
            Row.of("b", 9.1, 9.6),
            Row.of("b", 9.3, 9.9)
        );
        BatchOperator <?> batchData = new MemSourceBatchOp(df, "x1 string, x2 double, x3 double");
        BatchOperator <?> sampleOp = new StratifiedSampleWithSizeBatchOp()
            .setStrataCol("x1")
            .setStrataSizes("a:1,b:2");
        batchData.link(sampleOp).print();
    }
}

运行结果

| x1 | x2 | x3 | | —- | —- | —- |

| a | 0.0000 | 0.0000 |

| b | 9.1000 | 9.6000 |

| b | 0.2000 | 0.8000 |