Re: Use RDD like a Iterator
RDD.toLocalIterator return the partition one by one but with all elements in
the partition, which is not lazy calculated. Given the design of spark, it is
very hard to maintain the state of iterator across runJob.
def toLocalIterator: Iterator[T] = {
def collectPartition(p: Int): Array[T] = {
sc.runJob(this, (iter: Iterator[T]) = iter.toArray, Seq(p), allowLocal =
false).head
}
(0 until partitions.length).iterator.flatMap(i = collectPartition(i))
}
Thanks.
Zhan Zhang
On Oct 29, 2014, at 3:43 AM, Yanbo Liang yanboha...@gmail.com wrote:
RDD.toLocalIterator() is the suitable solution.
But I doubt whether it conform with the design principle of spark and RDD.
All RDD transform is lazily computed until it end with some actions.
2014-10-29 15:28 GMT+08:00 Sean Owen so...@cloudera.com:
Call RDD.toLocalIterator()?
https://spark.apache.org/docs/latest/api/java/org/apache/spark/rdd/RDD.html
On Wed, Oct 29, 2014 at 4:15 AM, Dai, Kevin yun...@ebay.com wrote:
Hi, ALL
I have a RDD[T], can I use it like a iterator.
That means I can compute every element of this RDD lazily.
Best Regards,
Kevin.
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Re: Use RDD like a Iterator
Call RDD.toLocalIterator()? https://spark.apache.org/docs/latest/api/java/org/apache/spark/rdd/RDD.html On Wed, Oct 29, 2014 at 4:15 AM, Dai, Kevin yun...@ebay.com wrote: Hi, ALL I have a RDD[T], can I use it like a iterator. That means I can compute every element of this RDD lazily. Best Regards, Kevin. - To unsubscribe, e-mail: user-unsubscr...@spark.apache.org For additional commands, e-mail: user-h...@spark.apache.org
Re: Use RDD like a Iterator
RDD.toLocalIterator() is the suitable solution. But I doubt whether it conform with the design principle of spark and RDD. All RDD transform is lazily computed until it end with some actions. 2014-10-29 15:28 GMT+08:00 Sean Owen so...@cloudera.com: Call RDD.toLocalIterator()? https://spark.apache.org/docs/latest/api/java/org/apache/spark/rdd/RDD.html On Wed, Oct 29, 2014 at 4:15 AM, Dai, Kevin yun...@ebay.com wrote: Hi, ALL I have a RDD[T], can I use it like a iterator. That means I can compute every element of this RDD lazily. Best Regards, Kevin. - To unsubscribe, e-mail: user-unsubscr...@spark.apache.org For additional commands, e-mail: user-h...@spark.apache.org
Use RDD like a Iterator
Hi, ALL I have a RDD[T], can I use it like a iterator. That means I can compute every element of this RDD lazily. Best Regards, Kevin.
Re: Use RDD like a Iterator
I think it is already lazily computed, or do you mean something else? Following is the signature of compute in RDD def compute(split: Partition, context: TaskContext): Iterator[T] Thanks. Zhan Zhang On Oct 28, 2014, at 8:15 PM, Dai, Kevin yun...@ebay.com wrote: Hi, ALL I have a RDD[T], can I use it like a iterator. That means I can compute every element of this RDD lazily. Best Regards, Kevin. -- CONFIDENTIALITY NOTICE NOTICE: This message is intended for the use of the individual or entity to which it is addressed and may contain information that is confidential, privileged and exempt from disclosure under applicable law. If the reader of this message is not the intended recipient, you are hereby notified that any printing, copying, dissemination, distribution, disclosure or forwarding of this communication is strictly prohibited. If you have received this communication in error, please contact the sender immediately and delete it from your system. Thank You.
RE: Use RDD like a Iterator
Would Rdd.map() do what you need? It will apply a function to every element of the rdd and return a resulting RDD. -Original Message- From: Zhan Zhang [zzh...@hortonworks.commailto:zzh...@hortonworks.com] Sent: Tuesday, October 28, 2014 11:23 PM Eastern Standard Time To: Dai, Kevin Cc: user@spark.apache.org Subject: Re: Use RDD like a Iterator I think it is already lazily computed, or do you mean something else? Following is the signature of compute in RDD def compute(split: Partition, context: TaskContext): Iterator[T] Thanks. Zhan Zhang On Oct 28, 2014, at 8:15 PM, Dai, Kevin yun...@ebay.commailto:yun...@ebay.com wrote: Hi, ALL I have a RDD[T], can I use it like a iterator. That means I can compute every element of this RDD lazily. Best Regards, Kevin. CONFIDENTIALITY NOTICE NOTICE: This message is intended for the use of the individual or entity to which it is addressed and may contain information that is confidential, privileged and exempt from disclosure under applicable law. If the reader of this message is not the intended recipient, you are hereby notified that any printing, copying, dissemination, distribution, disclosure or forwarding of this communication is strictly prohibited. If you have received this communication in error, please contact the sender immediately and delete it from your system. Thank You. The information contained in this e-mail is confidential and/or proprietary to Capital One and/or its affiliates. The information transmitted herewith is intended only for use by the individual or entity to which it is addressed. If the reader of this message is not the intended recipient, you are hereby notified that any review, retransmission, dissemination, distribution, copying or other use of, or taking of any action in reliance upon this information is strictly prohibited. If you have received this communication in error, please contact the sender and delete the material from your computer.
