/// <summary>
/// Build the union of a list of RDDs.
///
/// This supports unions() of RDDs with different serialized formats,
/// although this forces them to be reserialized using the default serializer:
///
/// >>> path = os.path.join(tempdir, "union-text.txt")
/// >>> with open(path, "w") as testFile:
/// ... _ = testFile.write("Hello")
/// >>> textFile = sc.textFile(path)
/// >>> textFile.collect()
/// [u'Hello']
/// >>> parallelized = sc.parallelize(["World!"])
/// >>> sorted(sc.union([textFile, parallelized]).collect())
/// [u'Hello', 'World!']
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="rdds"></param>
/// <returns></returns>
public RDD<T> Union<T>(IEnumerable<RDD<T>> rdds)
{
if (rdds == null || !rdds.Any())
return EmptyRDD<T>();
if (rdds.Count() == 1)
return rdds.First();
return new RDD<T>(SparkContextProxy.Union(rdds.Select(rdd => rdd.RddProxy)), this, rdds.First().serializedMode);
}
/// <summary>
/// Build the union of a list of RDDs.
///
/// This supports unions() of RDDs with different serialized formats,
/// although this forces them to be reserialized using the default serializer:
///
/// >>> path = os.path.join(tempdir, "union-text.txt")
/// >>> with open(path, "w") as testFile:
/// ... _ = testFile.write("Hello")
/// >>> textFile = sc.textFile(path)
/// >>> textFile.collect()
/// [u'Hello']
/// >>> parallelized = sc.parallelize(["World!"])
/// >>> sorted(sc.union([textFile, parallelized]).collect())
/// [u'Hello', 'World!']
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="rdds"></param>
/// <returns></returns>
public RDD <T> Union <T>(IEnumerable <RDD <T> > rdds)
{
if (rdds == null || rdds.Count() == 0)
{
return(EmptyRDD <T>());
}
if (rdds.Count() == 1)
{
return(rdds.First());
}
return(new RDD <T>(SparkContextProxy.Union(rdds.Select(rdd => rdd.RddProxy)), this, rdds.First().serializedMode));
}