Tablesaw

1. pom包

<dependency>
    <groupId>tech.tablesaw</groupId>
    <artifactId>tablesaw-core</artifactId>
    <version>LATEST</version>
</dependency>

2. reduce

2.1. 实例代码

double[] numbers = {1, 2, 3, 4};
DoubleColumn nc = DoubleColumn.create("nc", numbers);
        
System.out.println(nc.print());
Optional<Double> reduce = nc.reduce((DoubleBinaryOperator) (v1, v2) -> v1 + v2);
System.out.println(nc.sum());

3. 数据过滤排序

3.1. 实例代码

Table table = Table.read().csv("D:/Temp/student_csv.csv");
    //过滤语文分数大于等于80的学生
    Table filterResult = table
        .where(QuerySupport.all(t -> t.intColumn("语文分数").isGreaterThanOrEqualTo(80)));
    System.out.println(filterResult);
    //统计语文分数的平均值，最大值和最小值
    Table summarizeResult = table
        .summarize("语文分数", AggregateFunctions.mean, AggregateFunctions.max, AggregateFunctions.min)
        .apply();
    System.out.println(summarizeResult);

4. 运算

4.1. join运算

val tbl3 = tbl.joinOn("name").inner(tbl2)

  @Test
  public void joinTablesWithStringColumnsSuccess() throws IOException {
    Table t1 =
        Table.read()
            .usingOptions(
                CsvReadOptions.builderFromString(
                        Joiner.on(System.lineSeparator())
                            .join(
                                "TIME,TEMP SENSOR 1",
                                "13:21:50.430,23.7",
                                "13:21:51,23.1",
                                "13:21:52.451,24.2"))
                    .columnTypesToDetect(Arrays.asList(ColumnType.DOUBLE, ColumnType.TEXT)));

    Table t2 =
        Table.read()
            .usingOptions(
                CsvReadOptions.builderFromString(
                        Joiner.on(System.lineSeparator())
                            .join(
                                "TIME,TEMP SENSOR 2",
                                "13:21:50.430,24.9",
                                "13:21:51,25.2",
                                "13:21:52.451,26.1"))
                    .columnTypesToDetect(Arrays.asList(ColumnType.DOUBLE, ColumnType.TEXT)));

    Table joined = t1.joinOn("TIME").fullOuter(t2);
    assertEquals(3, joined.columnCount());
  }