PairRDDFunctions
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package rdd
Aggregate the values of each key, using given combine functions and a neutral "zero value".
Aggregate the values of each key, using given combine functions and a neutral "zero value". This function can return a different result type, U, than the type of the values in this RDD, V. Thus, we need one operation for merging a V into a U and one operation for merging two U's, as in scala.TraversableOnce. The former operation is used for merging values within a partition, and the latter is used for merging values between partitions. To avoid memory allocation, both of these functions are allowed to modify and return their first argument instead of creating a new U.
Aggregate the values of each key, using given combine functions and a neutral "zero value".
Aggregate the values of each key, using given combine functions and a neutral "zero value". This function can return a different result type, U, than the type of the values in this RDD, V. Thus, we need one operation for merging a V into a U and one operation for merging two U's, as in scala.TraversableOnce. The former operation is used for merging values within a partition, and the latter is used for merging values between partitions. To avoid memory allocation, both of these functions are allowed to modify and return their first argument instead of creating a new U.
Aggregate the values of each key, using given combine functions and a neutral "zero value".
Aggregate the values of each key, using given combine functions and a neutral "zero value". This function can return a different result type, U, than the type of the values in this RDD, V. Thus, we need one operation for merging a V into a U and one operation for merging two U's, as in scala.TraversableOnce. The former operation is used for merging values within a partition, and the latter is used for merging values between partitions. To avoid memory allocation, both of these functions are allowed to modify and return their first argument instead of creating a new U.
For each key k in this or other1 or other2 or other3,
return a resulting RDD that contains a tuple with the list of values
for that key in this, other1, other2 and other3.
For each key k in this or other1 or other2, return a resulting RDD that contains a
tuple with the list of values for that key in this, other1 and other2.
For each key k in this or other, return a resulting RDD that contains a tuple with the
list of values for that key in this as well as other.
For each key k in this or other1 or other2, return a resulting RDD that contains a
tuple with the list of values for that key in this, other1 and other2.
For each key k in this or other, return a resulting RDD that contains a tuple with the
list of values for that key in this as well as other.
For each key k in this or other1 or other2 or other3,
return a resulting RDD that contains a tuple with the list of values
for that key in this, other1, other2 and other3.
For each key k in this or other1 or other2, return a resulting RDD that contains a
tuple with the list of values for that key in this, other1 and other2.
For each key k in this or other, return a resulting RDD that contains a tuple with the
list of values for that key in this as well as other.
For each key k in this or other1 or other2 or other3,
return a resulting RDD that contains a tuple with the list of values
for that key in this, other1, other2 and other3.
Return the key-value pairs in this RDD to the master as a Map.
Return the key-value pairs in this RDD to the master as a Map.
Warning: this doesn't return a multimap (so if you have multiple values to the same key, only one value per key is preserved in the map returned)
this method should only be used if the resulting data is expected to be small, as all the data is loaded into the driver's memory.
Simplified version of combineByKeyWithClassTag that hash-partitions the resulting RDD using the existing partitioner/parallelism level.
Simplified version of combineByKeyWithClassTag that hash-partitions the resulting RDD using the existing partitioner/parallelism level. This method is here for backward compatibility. It does not provide combiner classtag information to the shuffle.
Simplified version of combineByKeyWithClassTag that hash-partitions the output RDD.
Simplified version of combineByKeyWithClassTag that hash-partitions the output RDD. This method is here for backward compatibility. It does not provide combiner classtag information to the shuffle.
Generic function to combine the elements for each key using a custom set of aggregation functions.
Generic function to combine the elements for each key using a custom set of aggregation functions. This method is here for backward compatibility. It does not provide combiner classtag information to the shuffle.
:: Experimental :: Simplified version of combineByKeyWithClassTag that hash-partitions the resulting RDD using the existing partitioner/parallelism level.
:: Experimental :: Simplified version of combineByKeyWithClassTag that hash-partitions the resulting RDD using the existing partitioner/parallelism level.
:: Experimental :: Simplified version of combineByKeyWithClassTag that hash-partitions the output RDD.
:: Experimental :: Simplified version of combineByKeyWithClassTag that hash-partitions the output RDD.
:: Experimental :: Generic function to combine the elements for each key using a custom set of aggregation functions.
:: Experimental :: Generic function to combine the elements for each key using a custom set of aggregation functions. Turns an RDD[(K, V)] into a result of type RDD[(K, C)], for a "combined type" C
Users provide three functions:
createCombiner, which turns a V into a C (e.g., creates a one-element list)mergeValue, to merge a V into a C (e.g., adds it to the end of a list)mergeCombiners, to combine two C's into a single one.In addition, users can control the partitioning of the output RDD, and whether to perform map-side aggregation (if a mapper can produce multiple items with the same key).
V and C can be different -- for example, one might group an RDD of type (Int, Int) into an RDD of type (Int, Seq[Int]).
Return approximate number of distinct values for each key in this RDD.
Return approximate number of distinct values for each key in this RDD.
The algorithm used is based on streamlib's implementation of "HyperLogLog in Practice: Algorithmic Engineering of a State of The Art Cardinality Estimation Algorithm", available here.
Relative accuracy. Smaller values create counters that require more space. It must be greater than 0.000017.
Return approximate number of distinct values for each key in this RDD.
Return approximate number of distinct values for each key in this RDD.
The algorithm used is based on streamlib's implementation of "HyperLogLog in Practice: Algorithmic Engineering of a State of The Art Cardinality Estimation Algorithm", available here.
Relative accuracy. Smaller values create counters that require more space. It must be greater than 0.000017.
number of partitions of the resulting RDD
Return approximate number of distinct values for each key in this RDD.
Return approximate number of distinct values for each key in this RDD.
The algorithm used is based on streamlib's implementation of "HyperLogLog in Practice: Algorithmic Engineering of a State of The Art Cardinality Estimation Algorithm", available here.
Relative accuracy. Smaller values create counters that require more space. It must be greater than 0.000017.
partitioner of the resulting RDD
Return approximate number of distinct values for each key in this RDD.
Return approximate number of distinct values for each key in this RDD.
The algorithm used is based on streamlib's implementation of "HyperLogLog in Practice: Algorithmic Engineering of a State of The Art Cardinality Estimation Algorithm", available here.
The relative accuracy is approximately 1.054 / sqrt(2^p). Setting a nonzero (sp is
greater than p) would trigger sparse representation of registers, which may reduce the
memory consumption and increase accuracy when the cardinality is small.
The precision value for the normal set.
p must be a value between 4 and sp if sp is not zero (32 max).
The precision value for the sparse set, between 0 and 32.
If sp equals 0, the sparse representation is skipped.
Partitioner to use for the resulting RDD.
Count the number of elements for each key, collecting the results to a local Map.
Count the number of elements for each key, collecting the results to a local Map.
This method should only be used if the resulting map is expected to be small, as the whole thing is loaded into the driver's memory. To handle very large results, consider using rdd.mapValues(_ => 1L).reduceByKey(_ + _), which returns an RDD[T, Long] instead of a map.
Approximate version of countByKey that can return a partial result if it does not finish within a timeout.
Approximate version of countByKey that can return a partial result if it does not finish within a timeout.
The confidence is the probability that the error bounds of the result will contain the true value. That is, if countApprox were called repeatedly with confidence 0.9, we would expect 90% of the results to contain the true count. The confidence must be in the range [0,1] or an exception will be thrown.
maximum time to wait for the job, in milliseconds
the desired statistical confidence in the result
a potentially incomplete result, with error bounds
Pass each value in the key-value pair RDD through a flatMap function without changing the keys; this also retains the original RDD's partitioning.
Merge the values for each key using an associative function and a neutral "zero value" which may be added to the result an arbitrary number of times, and must not change the result (e.g., Nil for list concatenation, 0 for addition, or 1 for multiplication.).
Merge the values for each key using an associative function and a neutral "zero value" which may be added to the result an arbitrary number of times, and must not change the result (e.g., Nil for list concatenation, 0 for addition, or 1 for multiplication.).
Merge the values for each key using an associative function and a neutral "zero value" which may be added to the result an arbitrary number of times, and must not change the result (e.g., Nil for list concatenation, 0 for addition, or 1 for multiplication.).
Perform a full outer join of this and other.
Perform a full outer join of this and other. For each element (k, v) in this, the
resulting RDD will either contain all pairs (k, (Some(v), Some(w))) for w in other, or
the pair (k, (Some(v), None)) if no elements in other have key k. Similarly, for each
element (k, w) in other, the resulting RDD will either contain all pairs
(k, (Some(v), Some(w))) for v in this, or the pair (k, (None, Some(w))) if no elements
in this have key k. Hash-partitions the resulting RDD into the given number of partitions.
Perform a full outer join of this and other.
Perform a full outer join of this and other. For each element (k, v) in this, the
resulting RDD will either contain all pairs (k, (Some(v), Some(w))) for w in other, or
the pair (k, (Some(v), None)) if no elements in other have key k. Similarly, for each
element (k, w) in other, the resulting RDD will either contain all pairs
(k, (Some(v), Some(w))) for v in this, or the pair (k, (None, Some(w))) if no elements
in this have key k. Hash-partitions the resulting RDD using the existing partitioner/
parallelism level.
Perform a full outer join of this and other.
Perform a full outer join of this and other. For each element (k, v) in this, the
resulting RDD will either contain all pairs (k, (Some(v), Some(w))) for w in other, or
the pair (k, (Some(v), None)) if no elements in other have key k. Similarly, for each
element (k, w) in other, the resulting RDD will either contain all pairs
(k, (Some(v), Some(w))) for v in this, or the pair (k, (None, Some(w))) if no elements
in this have key k. Uses the given Partitioner to partition the output RDD.
Group the values for each key in the RDD into a single sequence.
Group the values for each key in the RDD into a single sequence. Hash-partitions the resulting RDD with the existing partitioner/parallelism level. The ordering of elements within each group is not guaranteed, and may even differ each time the resulting RDD is evaluated.
This operation may be very expensive. If you are grouping in order to perform an
aggregation (such as a sum or average) over each key, using PairRDDFunctions.aggregateByKey
or PairRDDFunctions.reduceByKey will provide much better performance.
Group the values for each key in the RDD into a single sequence.
Group the values for each key in the RDD into a single sequence. Hash-partitions the
resulting RDD with into numPartitions partitions. The ordering of elements within
each group is not guaranteed, and may even differ each time the resulting RDD is evaluated.
As currently implemented, groupByKey must be able to hold all the key-value pairs for any key in memory. If a key has too many values, it can result in an OutOfMemoryError.
,This operation may be very expensive. If you are grouping in order to perform an
aggregation (such as a sum or average) over each key, using PairRDDFunctions.aggregateByKey
or PairRDDFunctions.reduceByKey will provide much better performance.
Group the values for each key in the RDD into a single sequence.
Group the values for each key in the RDD into a single sequence. Allows controlling the partitioning of the resulting key-value pair RDD by passing a Partitioner. The ordering of elements within each group is not guaranteed, and may even differ each time the resulting RDD is evaluated.
As currently implemented, groupByKey must be able to hold all the key-value pairs for any key in memory. If a key has too many values, it can result in an OutOfMemoryError.
,This operation may be very expensive. If you are grouping in order to perform an
aggregation (such as a sum or average) over each key, using PairRDDFunctions.aggregateByKey
or PairRDDFunctions.reduceByKey will provide much better performance.
Alias for cogroup.
Alias for cogroup.
Alias for cogroup.
Return an RDD containing all pairs of elements with matching keys in this and other.
Return an RDD containing all pairs of elements with matching keys in this and other. Each
pair of elements will be returned as a (k, (v1, v2)) tuple, where (k, v1) is in this and
(k, v2) is in other. Performs a hash join across the cluster.
Return an RDD containing all pairs of elements with matching keys in this and other.
Return an RDD containing all pairs of elements with matching keys in this and other. Each
pair of elements will be returned as a (k, (v1, v2)) tuple, where (k, v1) is in this and
(k, v2) is in other. Performs a hash join across the cluster.
Return an RDD containing all pairs of elements with matching keys in this and other.
Return an RDD containing all pairs of elements with matching keys in this and other. Each
pair of elements will be returned as a (k, (v1, v2)) tuple, where (k, v1) is in this and
(k, v2) is in other. Uses the given Partitioner to partition the output RDD.
Return an RDD with the keys of each tuple.
Perform a left outer join of this and other.
Perform a left outer join of this and other. For each element (k, v) in this, the
resulting RDD will either contain all pairs (k, (v, Some(w))) for w in other, or the
pair (k, (v, None)) if no elements in other have key k. Hash-partitions the output
into numPartitions partitions.
Perform a left outer join of this and other.
Perform a left outer join of this and other. For each element (k, v) in this, the
resulting RDD will either contain all pairs (k, (v, Some(w))) for w in other, or the
pair (k, (v, None)) if no elements in other have key k. Hash-partitions the output
using the existing partitioner/parallelism level.
Perform a left outer join of this and other.
Perform a left outer join of this and other. For each element (k, v) in this, the
resulting RDD will either contain all pairs (k, (v, Some(w))) for w in other, or the
pair (k, (v, None)) if no elements in other have key k. Uses the given Partitioner to
partition the output RDD.
Return the list of values in the RDD for key key.
Return the list of values in the RDD for key key. This operation is done efficiently if the
RDD has a known partitioner by only searching the partition that the key maps to.
Pass each value in the key-value pair RDD through a map function without changing the keys; this also retains the original RDD's partitioning.
Return a copy of the RDD partitioned using the specified partitioner.
Merge the values for each key using an associative and commutative reduce function.
Merge the values for each key using an associative and commutative reduce function. This will also perform the merging locally on each mapper before sending results to a reducer, similarly to a "combiner" in MapReduce. Output will be hash-partitioned with the existing partitioner/ parallelism level.
Merge the values for each key using an associative and commutative reduce function.
Merge the values for each key using an associative and commutative reduce function. This will also perform the merging locally on each mapper before sending results to a reducer, similarly to a "combiner" in MapReduce. Output will be hash-partitioned with numPartitions partitions.
Merge the values for each key using an associative and commutative reduce function.
Merge the values for each key using an associative and commutative reduce function. This will also perform the merging locally on each mapper before sending results to a reducer, similarly to a "combiner" in MapReduce.
Merge the values for each key using an associative and commutative reduce function, but return the results immediately to the master as a Map.
Merge the values for each key using an associative and commutative reduce function, but return the results immediately to the master as a Map. This will also perform the merging locally on each mapper before sending results to a reducer, similarly to a "combiner" in MapReduce.
Perform a right outer join of this and other.
Perform a right outer join of this and other. For each element (k, w) in other, the
resulting RDD will either contain all pairs (k, (Some(v), w)) for v in this, or the
pair (k, (None, w)) if no elements in this have key k. Hash-partitions the resulting
RDD into the given number of partitions.
Perform a right outer join of this and other.
Perform a right outer join of this and other. For each element (k, w) in other, the
resulting RDD will either contain all pairs (k, (Some(v), w)) for v in this, or the
pair (k, (None, w)) if no elements in this have key k. Hash-partitions the resulting
RDD using the existing partitioner/parallelism level.
Perform a right outer join of this and other.
Perform a right outer join of this and other. For each element (k, w) in other, the
resulting RDD will either contain all pairs (k, (Some(v), w)) for v in this, or the
pair (k, (None, w)) if no elements in this have key k. Uses the given Partitioner to
partition the output RDD.
Return a subset of this RDD sampled by key (via stratified sampling).
Return a subset of this RDD sampled by key (via stratified sampling).
Create a sample of this RDD using variable sampling rates for different keys as specified by
fractions, a key to sampling rate map, via simple random sampling with one pass over the
RDD, to produce a sample of size that's approximately equal to the sum of
math.ceil(numItems * samplingRate) over all key values.
whether to sample with or without replacement
map of specific keys to sampling rates
seed for the random number generator
RDD containing the sampled subset
Return a subset of this RDD sampled by key (via stratified sampling) containing exactly math.ceil(numItems * samplingRate) for each stratum (group of pairs with the same key).
Return a subset of this RDD sampled by key (via stratified sampling) containing exactly math.ceil(numItems * samplingRate) for each stratum (group of pairs with the same key).
This method differs from sampleByKey in that we make additional passes over the RDD to create a sample size that's exactly equal to the sum of math.ceil(numItems * samplingRate) over all key values with a 99.99% confidence. When sampling without replacement, we need one additional pass over the RDD to guarantee sample size; when sampling with replacement, we need two additional passes.
whether to sample with or without replacement
map of specific keys to sampling rates
seed for the random number generator
RDD containing the sampled subset
Output the RDD to any Hadoop-supported storage system, using a Hadoop JobConf object for that storage system.
Output the RDD to any Hadoop-supported storage system, using a Hadoop JobConf object for that storage system. The JobConf should set an OutputFormat and any output paths required (e.g. a table name to write to) in the same way as it would be configured for a Hadoop MapReduce job.
Output the RDD to any Hadoop-supported file system, using a Hadoop OutputFormat class
supporting the key and value types K and V in this RDD.
Output the RDD to any Hadoop-supported file system, using a Hadoop OutputFormat class
supporting the key and value types K and V in this RDD.
We should make sure our tasks are idempotent when speculation is enabled, i.e. do not use output committer that writes data directly. There is an example in https://issues.apache.org/jira/browse/SPARK-10063 to show the bad result of using direct output committer with speculation enabled.
Output the RDD to any Hadoop-supported file system, using a Hadoop OutputFormat class
supporting the key and value types K and V in this RDD.
Output the RDD to any Hadoop-supported file system, using a Hadoop OutputFormat class
supporting the key and value types K and V in this RDD. Compress with the supplied codec.
Output the RDD to any Hadoop-supported file system, using a Hadoop OutputFormat class
supporting the key and value types K and V in this RDD.
Output the RDD to any Hadoop-supported file system, using a Hadoop OutputFormat class
supporting the key and value types K and V in this RDD. Compress the result with the
supplied codec.
Output the RDD to any Hadoop-supported file system, using a Hadoop OutputFormat class
supporting the key and value types K and V in this RDD.
Output the RDD to any Hadoop-supported storage system with new Hadoop API, using a Hadoop Configuration object for that storage system.
Output the RDD to any Hadoop-supported storage system with new Hadoop API, using a Hadoop Configuration object for that storage system. The Conf should set an OutputFormat and any output paths required (e.g. a table name to write to) in the same way as it would be configured for a Hadoop MapReduce job.
We should make sure our tasks are idempotent when speculation is enabled, i.e. do not use output committer that writes data directly. There is an example in https://issues.apache.org/jira/browse/SPARK-10063 to show the bad result of using direct output committer with speculation enabled.
Output the RDD to any Hadoop-supported file system, using a new Hadoop API OutputFormat
(mapreduce.OutputFormat) object supporting the key and value types K and V in this RDD.
Output the RDD to any Hadoop-supported file system, using a new Hadoop API OutputFormat
(mapreduce.OutputFormat) object supporting the key and value types K and V in this RDD.
Return an RDD with the pairs from this whose keys are not in other.
Return an RDD with the pairs from this whose keys are not in other.
Return an RDD with the pairs from this whose keys are not in other.
Return an RDD with the pairs from this whose keys are not in other.
Uses this partitioner/partition size, because even if other is huge, the resulting
RDD will be less than or equal to us.
Return an RDD with the values of each tuple.
Extra functions available on RDDs of (key, value) pairs through an implicit conversion.