Nov 11, 2018 Update elements by reassigning them. Given a new, mutable Scala Map : scala> var states = scala.collection.mutable.Map[String, String]() states

Scala parallel collections allow you to solve data parallelism problems in ms getOrElseUpdate(k, d), If key k is defined in map ms, return its associated value.

All gists Back to GitHub Sign in Sign up Sign in Sign up {{ message }} No Spark shuffle block is larger than 2GB (Integer.MAX_VALUE bytes) therefore you need additional / smaller partitions.You should adjust spark.default.parallelism and spark.sql.shuffle.partitions (default 200) such that the number of partitions can accommodate your data without reaching the 2GB limit (you could try aiming for 256MB / partition so for 200GB you get 800 partitions). The following examples show how to use scala.collection.mutable.Set.These examples are extracted from open source projects. You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. /** * Convert this promise to a Scala future. *

* This is equivalent to FutureConverters.toScala(this), however, it converts the wrapped completion stage to * a future rather than this, which means if the wrapped completion stage itself wraps a Scala future, it will * simply return that wrapped future.

Getorelseupdate scala

The scala package contains core types like Int, Float, Array or Option which are accessible in all Scala compilation units without explicit qualification or imports. As I understand, TrieMap.getOrElseUpdate is still not truly atomic, and this fixes only returned result (it could return different instances for different callers before this fix), so the updater function still might be called several times, as documentation (for 2.11.7) says: Note: This method will invoke op at most once. ms getOrElseUpdate (k, d) If key k is defined in map ms, return its associated value. Otherwise, update ms with the mapping k -> d and return d. Removals: ms -= k: Removes mapping with key k from ms as a side effect and returns ms itself. ms -= (k, l, m) Removes mappings with the given keys from ms as a side effect and returns ms itself. ms --= ks // not possible with Int counts.getOrElseUpdate(key, 0) += 1 // but with a modifiable counter counts.getOrElseUpdate(key, new Counter).increment Somehow I'm always expecting to have the following functionality with a mutable map (somewhat similar to transform but without returning a new collection and on a specific key with a default value): Note: getOrElseUpdate is not an atomic operation in EhCache and is implemented as a get followed by computing the value, then a set.

This is typically logic you would write in Java, and it looks great in some ways: it uses pattern matching, the tuple arrow ( -> ), etc. But it turns out that Scala collections already provide the getOrElseUpdate method on mutable maps. The 8 lines above translate simply into: 1 2. def getModelState(modelPrefixedId: String) = modelStates.

Otherwise, update ms with the mapping k -> d and return d. Removals: ms -= k: Removes mapping with key k from ms as a side effect and returns ms itself. ms -= (k, l, m) Removes mappings with the given keys from ms as a side effect and returns ms itself. ms --= ks // not possible with Int counts.getOrElseUpdate(key, 0) += 1 // but with a modifiable counter counts.getOrElseUpdate(key, new Counter).increment Somehow I'm always expecting to have the following functionality with a mutable map (somewhat similar to transform but without returning a new collection and on a specific key with a default value): Note: getOrElseUpdate is not an atomic operation in EhCache and is implemented as a get followed by computing the value, then a set.

Can the highlighted with comment line be rewritten using the getOrElseUpdate method? P.S. I am only at the 4th part of the "Scala for the impatient", so please don't teach me now about functional Scala which, I am sure, can be more beautiful here. Thanks.

runtime.MacroRuntimes.standardMacroRuntime(MacroRuntimes. Runner.main(Runner.scala) Caused by: java.awt.HeadlessException at getOrElseUpdate(MapLike.scala:189) at scala.collection.mutable.AbstractMap. Feb 11, 2021 HashMap.getOrElseUpdate(HashMap.scala:86) ~[scala-library-2.12.10.jar:?] at org.neo4j.cypher.internal.compiler.helpers. scala> val results = sqlContext.sql("SELECT * FROM my_keyspace.my_table") getOrElseUpdate(BlockManager.scala:711) at org.apache.spark.rdd.RDD. Sep 10, 2020 getOrElseUpdate(BlockManager.scala:881) at org.apache.spark.rdd.RDD.

* * val cache = new ConcurrentHashMap().asScala * cache.getOrElseUpdate("foo", "bar") // BAD idea * package com.yahoo.maha import java.sql.ResultSet package object jdbc { type Seq[+A] = scala.collection.immutable.Seq[A] val Seq = scala.collection.immutable.Seq type List[+A] = scala.collection.immutable.List[A] val List = scala.collection.immutable.List implicit class RowData(rs: ResultSet) { def apply(columnNumber: Int): Any = rs.getObject(columnNumber) def apply(columnName: String): Any = rs.getObject(columnName) def toIterator[E](rowMapper: ResultSet => E): Iterator[E] = new Iterator[E Note that I don't want to use getOrElseUpdate here if I don't have to because it gets pretty verbose when you have nested maps and obscures what's actually going on in the code: m.getOrElseUpdate(1992, Map[String, Set[String]]()).getOrElseUpdate("foo", Set[String]()) ++= "bar" So I'm overriding HashMap's "default" method.
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Hi! I would like to have an implicit conversion with caching of Nov 9, 2020 Learn about Play's caching API with Scala. Future[Option[T]] – Retrieve the value from the cache if it exists; getOrElseUpdate[T](key: String, Nov 23, 2020 getOrElseUpdate(Map.scala:80) at com.atlassian.servicedesk.internal.feature. customer.request.RequestListProviderScala$$anonfun$15.apply( Scala collections provide many common operations for constructing them, Mutable Map s have a convenient getOrElseUpdate function, that allows you to look Nov 11, 2018 Update elements by reassigning them. Given a new, mutable Scala Map : scala> var states = scala.collection.mutable.Map[String, String]() states ms getOrElseUpdate (k, d), If key k is defined in map ms , return its associated value. Otherwise, update ms with the mapping k -> d and return d .

Scala’s Predef object offers an implicit conversion that lets you write key -> value as an alternate syntax ms getOrElseUpdate (k, d) If key k is defined in map But the method getOrElseUpdate of scala.co The ScalaDoc states that a scala.collection.concurrent.TrieMap is thread-safe: A concurrent hash-trie or TrieMap is a concurrent thread-safe lock-free implementation of a hash array mapped trie. Bu If there is a difference, I still wouldn't expect it to necessarily work out in favor of using Java for Scala (and vice-versa, I suppose): by removing the Scala code from a more normal context, you might make the microbenchmarking results even less relevant to normal usage than microbenchmarks usually are.
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The last item among the control abstraction is the for expression. The Scala's for loop is a swiss army knife of iterations. Scala for loop is just a syntactic sugar.

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AbstractMap.getOrElseUpdate(Map.scala:80) [error] at scala.reflect.macros. runtime.MacroRuntimes.standardMacroRuntime(MacroRuntimes.

Package structure . The scala package contains core types like Int, Float, Array or Option which are accessible in all Scala compilation units without explicit qualification or imports. As I understand, TrieMap.getOrElseUpdate is still not truly atomic, and this fixes only returned result (it could return different instances for different callers before this fix), so the updater function still might be called several times, as documentation (for 2.11.7) says: Note: This method will invoke op at most once. ms getOrElseUpdate (k, d) If key k is defined in map ms, return its associated value. Otherwise, update ms with the mapping k -> d and return d.

Solved: Despite adding the following, --conf. Hey AK, Following is the stack trace: 10:13:28,194 WARN [TaskSetManager] Lost task 8.0 in stage 1.0 (TID 4, hostname

Notable packages include: scala.collection and its sub-packages contain Scala's collections framework mutable.HashMap getOrElseUpdate not reentrant in 2.12 Showing 1-3 of 3 messages.

This is a very common usage pattern for any cache. This one API call will probably suffice for the great majority of applications. 4.3.