[SPARK-7150] SparkContext.range() and SQLContext.range()
This PR is based on #6081, thanks adrian-wang.
Closes #6081
Author: Daoyuan Wang <daoyuan.wang@intel.com>
Author: Davies Liu <davies@databricks.com>
Closes #6230 from davies/range and squashes the following commits:
d3ce5fe [Davies Liu] add tests
789eda5 [Davies Liu] add range() in Python
4590208 [Davies Liu] Merge commit 'refs/pull/6081/head' of github.com:apache/spark into range
cbf5200 [Daoyuan Wang] let's add python support in a separate PR
f45e3b2 [Daoyuan Wang] remove redundant toLong
617da76 [Daoyuan Wang] fix safe marge for corner cases
867c417 [Daoyuan Wang] fix
13dbe84 [Daoyuan Wang] update
bd998ba [Daoyuan Wang] update comments
d3a0c1b [Daoyuan Wang] add range api()
(cherry picked from commit c2437de189
)
Signed-off-by: Reynold Xin <rxin@databricks.com>
This commit is contained in:
parent
9d0b7fb714
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7fcbb2ccaf
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@ -697,6 +697,78 @@ class SparkContext(config: SparkConf) extends Logging with ExecutorAllocationCli
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new ParallelCollectionRDD[T](this, seq, numSlices, Map[Int, Seq[String]]())
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}
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/**
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* Creates a new RDD[Long] containing elements from `start` to `end`(exclusive), increased by
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* `step` every element.
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*
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* @note if we need to cache this RDD, we should make sure each partition does not exceed limit.
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*
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* @param start the start value.
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* @param end the end value.
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* @param step the incremental step
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* @param numSlices the partition number of the new RDD.
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* @return
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*/
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def range(
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start: Long,
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end: Long,
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step: Long = 1,
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numSlices: Int = defaultParallelism): RDD[Long] = withScope {
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assertNotStopped()
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// when step is 0, range will run infinitely
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require(step != 0, "step cannot be 0")
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val numElements: BigInt = {
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val safeStart = BigInt(start)
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val safeEnd = BigInt(end)
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if ((safeEnd - safeStart) % step == 0 || safeEnd > safeStart ^ step > 0) {
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(safeEnd - safeStart) / step
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} else {
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// the remainder has the same sign with range, could add 1 more
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(safeEnd - safeStart) / step + 1
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}
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}
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parallelize(0 until numSlices, numSlices).mapPartitionsWithIndex((i, _) => {
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val partitionStart = (i * numElements) / numSlices * step + start
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val partitionEnd = (((i + 1) * numElements) / numSlices) * step + start
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def getSafeMargin(bi: BigInt): Long =
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if (bi.isValidLong) {
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bi.toLong
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} else if (bi > 0) {
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Long.MaxValue
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} else {
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Long.MinValue
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}
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val safePartitionStart = getSafeMargin(partitionStart)
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val safePartitionEnd = getSafeMargin(partitionEnd)
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new Iterator[Long] {
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private[this] var number: Long = safePartitionStart
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private[this] var overflow: Boolean = false
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override def hasNext =
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if (!overflow) {
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if (step > 0) {
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number < safePartitionEnd
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} else {
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number > safePartitionEnd
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}
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} else false
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override def next() = {
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val ret = number
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number += step
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if (number < ret ^ step < 0) {
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// we have Long.MaxValue + Long.MaxValue < Long.MaxValue
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// and Long.MinValue + Long.MinValue > Long.MinValue, so iff the step causes a step
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// back, we are pretty sure that we have an overflow.
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overflow = true
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}
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ret
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}
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}
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})
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}
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/** Distribute a local Scala collection to form an RDD.
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*
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* This method is identical to `parallelize`.
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@ -319,6 +319,22 @@ class SparkContext(object):
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with SparkContext._lock:
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SparkContext._active_spark_context = None
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def range(self, start, end, step=1, numSlices=None):
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"""
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Create a new RDD of int containing elements from `start` to `end`
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(exclusive), increased by `step` every element.
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:param start: the start value
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:param end: the end value (exclusive)
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:param step: the incremental step (default: 1)
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:param numSlices: the number of partitions of the new RDD
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:return: An RDD of int
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>>> sc.range(1, 7, 2).collect()
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[1, 3, 5]
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"""
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return self.parallelize(xrange(start, end, step), numSlices)
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def parallelize(self, c, numSlices=None):
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"""
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Distribute a local Python collection to form an RDD. Using xrange
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@ -122,6 +122,26 @@ class SQLContext(object):
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"""Returns a :class:`UDFRegistration` for UDF registration."""
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return UDFRegistration(self)
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def range(self, start, end, step=1, numPartitions=None):
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"""
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Create a :class:`DataFrame` with single LongType column named `id`,
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containing elements in a range from `start` to `end` (exclusive) with
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step value `step`.
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:param start: the start value
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:param end: the end value (exclusive)
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:param step: the incremental step (default: 1)
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:param numPartitions: the number of partitions of the DataFrame
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:return: A new DataFrame
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>>> sqlContext.range(1, 7, 2).collect()
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[Row(id=1), Row(id=3), Row(id=5)]
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"""
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if numPartitions is None:
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numPartitions = self._sc.defaultParallelism
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jdf = self._ssql_ctx.range(int(start), int(end), int(step), int(numPartitions))
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return DataFrame(jdf, self)
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@ignore_unicode_prefix
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def registerFunction(self, name, f, returnType=StringType()):
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"""Registers a lambda function as a UDF so it can be used in SQL statements.
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@ -117,6 +117,11 @@ class SQLTests(ReusedPySparkTestCase):
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ReusedPySparkTestCase.tearDownClass()
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shutil.rmtree(cls.tempdir.name, ignore_errors=True)
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def test_range(self):
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self.assertEqual(self.sqlCtx.range(1, 1).count(), 0)
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self.assertEqual(self.sqlCtx.range(1, 0, -1).count(), 1)
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self.assertEqual(self.sqlCtx.range(0, 1 << 40, 1 << 39).count(), 2)
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def test_explode(self):
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from pyspark.sql.functions import explode
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d = [Row(a=1, intlist=[1, 2, 3], mapfield={"a": "b"})]
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@ -444,6 +444,11 @@ class AddFileTests(PySparkTestCase):
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class RDDTests(ReusedPySparkTestCase):
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def test_range(self):
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self.assertEqual(self.sc.range(1, 1).count(), 0)
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self.assertEqual(self.sc.range(1, 0, -1).count(), 1)
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self.assertEqual(self.sc.range(0, 1 << 40, 1 << 39).count(), 2)
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def test_id(self):
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rdd = self.sc.parallelize(range(10))
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id = rdd.id()
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@ -684,6 +684,37 @@ class SQLContext(@transient val sparkContext: SparkContext)
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catalog.unregisterTable(Seq(tableName))
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}
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/**
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* :: Experimental ::
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* Creates a [[DataFrame]] with a single [[LongType]] column named `id`, containing elements
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* in an range from `start` to `end`(exclusive) with step value 1.
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*
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* @since 1.4.0
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* @group dataframe
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*/
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@Experimental
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def range(start: Long, end: Long): DataFrame = {
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createDataFrame(
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sparkContext.range(start, end).map(Row(_)),
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StructType(StructField("id", LongType, nullable = false) :: Nil))
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}
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/**
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* :: Experimental ::
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* Creates a [[DataFrame]] with a single [[LongType]] column named `id`, containing elements
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* in an range from `start` to `end`(exclusive) with an step value, with partition number
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* specified.
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*
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* @since 1.4.0
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* @group dataframe
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*/
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@Experimental
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def range(start: Long, end: Long, step: Long, numPartitions: Int): DataFrame = {
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createDataFrame(
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sparkContext.range(start, end, step, numPartitions).map(Row(_)),
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StructType(StructField("id", LongType, nullable = false) :: Nil))
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}
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/**
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* Executes a SQL query using Spark, returning the result as a [[DataFrame]]. The dialect that is
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* used for SQL parsing can be configured with 'spark.sql.dialect'.
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@ -532,4 +532,44 @@ class DataFrameSuite extends QueryTest {
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val p = df.logicalPlan.asInstanceOf[Project].child.asInstanceOf[Project]
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assert(!p.child.isInstanceOf[Project])
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}
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test("SPARK-7150 range api") {
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// numSlice is greater than length
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val res1 = TestSQLContext.range(0, 10, 1, 15).select("id")
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assert(res1.count == 10)
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assert(res1.agg(sum("id")).as("sumid").collect() === Seq(Row(45)))
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val res2 = TestSQLContext.range(3, 15, 3, 2).select("id")
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assert(res2.count == 4)
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assert(res2.agg(sum("id")).as("sumid").collect() === Seq(Row(30)))
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val res3 = TestSQLContext.range(1, -2).select("id")
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assert(res3.count == 0)
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// start is positive, end is negative, step is negative
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val res4 = TestSQLContext.range(1, -2, -2, 6).select("id")
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assert(res4.count == 2)
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assert(res4.agg(sum("id")).as("sumid").collect() === Seq(Row(0)))
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// start, end, step are negative
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val res5 = TestSQLContext.range(-3, -8, -2, 1).select("id")
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assert(res5.count == 3)
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assert(res5.agg(sum("id")).as("sumid").collect() === Seq(Row(-15)))
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// start, end are negative, step is positive
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val res6 = TestSQLContext.range(-8, -4, 2, 1).select("id")
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assert(res6.count == 2)
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assert(res6.agg(sum("id")).as("sumid").collect() === Seq(Row(-14)))
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val res7 = TestSQLContext.range(-10, -9, -20, 1).select("id")
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assert(res7.count == 0)
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val res8 = TestSQLContext.range(Long.MinValue, Long.MaxValue, Long.MaxValue, 100).select("id")
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assert(res8.count == 3)
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assert(res8.agg(sum("id")).as("sumid").collect() === Seq(Row(-3)))
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val res9 = TestSQLContext.range(Long.MaxValue, Long.MinValue, Long.MinValue, 100).select("id")
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assert(res9.count == 2)
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assert(res9.agg(sum("id")).as("sumid").collect() === Seq(Row(Long.MaxValue - 1)))
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}
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}
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