本文整理了Java中org.apache.spark.sql.functions.expr()方法的一些代码示例，展示了functions.expr()的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。functions.expr()方法的具体详情如下：
包路径：org.apache.spark.sql.functions
类名称：functions
方法名：expr

functions.expr介绍

暂无

代码示例

代码示例来源：origin: org.apache.spark/spark-sql

@Test
public void testSelect() {
 List<Integer> data = Arrays.asList(2, 6);
 Dataset<Integer> ds = spark.createDataset(data, Encoders.INT());
 Dataset<Tuple2<Integer, String>> selected = ds.select(
  expr("value + 1"),
  col("value").cast("string")).as(Encoders.tuple(Encoders.INT(), Encoders.STRING()));
 Assert.assertEquals(
  Arrays.asList(tuple2(3, "2"), tuple2(7, "6")),
  selected.collectAsList());
}

代码示例来源：origin: org.apache.spark/spark-sql_2.11

@Test
public void testSelect() {
 List<Integer> data = Arrays.asList(2, 6);
 Dataset<Integer> ds = spark.createDataset(data, Encoders.INT());
 Dataset<Tuple2<Integer, String>> selected = ds.select(
  expr("value + 1"),
  col("value").cast("string")).as(Encoders.tuple(Encoders.INT(), Encoders.STRING()));
 Assert.assertEquals(
  Arrays.asList(tuple2(3, "2"), tuple2(7, "6")),
  selected.collectAsList());
}

代码示例来源：origin: org.apache.spark/spark-sql_2.10

@Test
public void testSelect() {
 List<Integer> data = Arrays.asList(2, 6);
 Dataset<Integer> ds = spark.createDataset(data, Encoders.INT());
 Dataset<Tuple2<Integer, String>> selected = ds.select(
  expr("value + 1"),
  col("value").cast("string")).as(Encoders.tuple(Encoders.INT(), Encoders.STRING()));
 Assert.assertEquals(
  Arrays.asList(tuple2(3, "2"), tuple2(7, "6")),
  selected.collectAsList());
}

代码示例来源：origin: org.apache.spark/spark-sql

@Test
public void testTupleEncoderSchema() {
 Encoder<Tuple2<String, Tuple2<String,String>>> encoder =
  Encoders.tuple(Encoders.STRING(), Encoders.tuple(Encoders.STRING(), Encoders.STRING()));
 List<Tuple2<String, Tuple2<String, String>>> data = Arrays.asList(tuple2("1", tuple2("a", "b")),
  tuple2("2", tuple2("c", "d")));
 Dataset<Row> ds1 = spark.createDataset(data, encoder).toDF("value1", "value2");
 JavaPairRDD<String, Tuple2<String, String>> pairRDD = jsc.parallelizePairs(data);
 Dataset<Row> ds2 = spark.createDataset(JavaPairRDD.toRDD(pairRDD), encoder)
  .toDF("value1", "value2");
 Assert.assertEquals(ds1.schema(), ds2.schema());
 Assert.assertEquals(ds1.select(expr("value2._1")).collectAsList(),
  ds2.select(expr("value2._1")).collectAsList());
}

代码示例来源：origin: org.apache.spark/spark-sql_2.11

@Test
public void testTupleEncoderSchema() {
 Encoder<Tuple2<String, Tuple2<String,String>>> encoder =
  Encoders.tuple(Encoders.STRING(), Encoders.tuple(Encoders.STRING(), Encoders.STRING()));
 List<Tuple2<String, Tuple2<String, String>>> data = Arrays.asList(tuple2("1", tuple2("a", "b")),
  tuple2("2", tuple2("c", "d")));
 Dataset<Row> ds1 = spark.createDataset(data, encoder).toDF("value1", "value2");
 JavaPairRDD<String, Tuple2<String, String>> pairRDD = jsc.parallelizePairs(data);
 Dataset<Row> ds2 = spark.createDataset(JavaPairRDD.toRDD(pairRDD), encoder)
  .toDF("value1", "value2");
 Assert.assertEquals(ds1.schema(), ds2.schema());
 Assert.assertEquals(ds1.select(expr("value2._1")).collectAsList(),
  ds2.select(expr("value2._1")).collectAsList());
}