logo
down
shadow

SCALA QUESTIONS

Optimizing the Spark Code
Optimizing the Spark Code
I wish this help you As @a-spoty-spot commented, if there aren't too many unique values of lst - your best approach is to change it to Set (which removes duplicates) and use broadcast.Otherwise (if that list of unique keys can still be huge) - here's
TAG : scala
Date : November 25 2020, 11:01 PM , By : Josh Naval
Is this a bug of scala's specialized?
Is this a bug of scala's specialized?
will help you This is a bug (also reproduces on 2.11.x). I've contacted the guys at LightBend, and this is definitely a quirk with the code generation for specialization and path dependent types. I've narrowed it down to a slim reproduce:
TAG : scala
Date : November 25 2020, 11:01 PM , By : Sarit Baicher
Try and getOrElse scala
Try and getOrElse scala
hop of those help? , I think you misunderstood Try. and .getOrElseDefinition of Try :
TAG : scala
Date : November 24 2020, 11:01 PM , By : Cychun
Can I use Enumerations as type parameters in Scala?
Can I use Enumerations as type parameters in Scala?
I think the issue was by ths following , I'd like to use an Enumeration as a type parameter by the compiler is giving me grief. , You can write
TAG : scala
Date : November 23 2020, 11:01 PM , By : user6064865
In Scaldi, I loaded my own typesafe config, how can I set Scaldi to make it available?
In Scaldi, I loaded my own typesafe config, how can I set Scaldi to make it available?
I wish did fix the issue. I want to load my own config from a configuration file. After loading the config I want to be able to inject the config values using Scaldi. Here is the code where I load the typesafe config. How can I adjust this code so th
TAG : scala
Date : November 22 2020, 11:00 PM , By : S K DAS
How to chain operations in idiomatic scala
How to chain operations in idiomatic scala
this will help I want to apply a list of regex to a string. My current approach is not very functional , I think this does what you're looking for.
TAG : scala
Date : November 21 2020, 11:01 PM , By : Vladimir Makarevich
How to generate Path with DateTimeFormat for pattern yyyy/mm/dd/HH
How to generate Path with DateTimeFormat for pattern yyyy/mm/dd/HH
hope this fix your issue You have used LocalDate which is a date-only class, it explicitly does not contain time information (this is different to java.sql.Date which contains time and date info). Therefore Joda cannot render the "HH" as hour, as it
TAG : scala
Date : November 21 2020, 11:01 PM , By : xianyu
Function with Generic type that extend class
Function with Generic type that extend class
fixed the issue. Will look into that further The issue is that in the definition of setMapping, you are telling the compiler only that T is a subtype of EventBase. So when you call setMapping and inside the call you have evt.userName, the compiler ca
TAG : scala
Date : November 20 2020, 11:01 PM , By : Abhi Nandan
When to create an Akka Actor
When to create an Akka Actor
it should still fix some issue If you use one Actor requests are queued inside the actor mail box and are processed one by one by the actor. This is sequential and not recommended.Thats why it is said
TAG : scala
Date : November 17 2020, 11:01 PM , By : mchave10
Scala append Seq in with a string in a List Map or Foreach
Scala append Seq in with a string in a List Map or Foreach
should help you out I'm looking to append a val adminEmailSeq = Seq.empty[String] from a List of object attribute. , From the description I assume that you need Emails from Admins
TAG : scala
Date : November 17 2020, 11:01 PM , By : seanchen2016
Accessing a Scala Trait method inside another method
Accessing a Scala Trait method inside another method
hop of those help? I am writing a trait that contains a function: , You can use self type
TAG : scala
Date : November 17 2020, 11:01 PM , By : Kadria Saad
Scala: force type parameter to be a case class
Scala: force type parameter to be a case class
around this issue The problem is that SomeExternalBuilder will only accept a case class as argument ("case class expected: M"), so it does not compile.
TAG : scala
Date : November 17 2020, 11:01 PM , By : Sar Sou
Can non-persistent data structures be used in a purely functional way?
Can non-persistent data structures be used in a purely functional way?
it helps some times I'm pretty sure that a feature like alias analysis (checking if data is used elsewhere) is not part of the Scala compiler (nor part of other FP languages like Haskell and Clojure). The collections API in Scala (for example) is exp
TAG : scala
Date : November 17 2020, 11:01 PM , By : Milena Anaya
Shuffle some sequence of List in Scala
Shuffle some sequence of List in Scala
this one helps. val a:List = List(1,2,Random.shuffle(3,4,5)) this line would give type errorReason
TAG : scala
Date : November 16 2020, 11:00 PM , By : Bc Bc
GraphX-Spark: error graph.vertices.filter
GraphX-Spark: error graph.vertices.filter
seems to work fine At the commend I made a mistake, thinking Score is type. Most of time if you do pattern matching, it's safe to use lower-case letters. (lowercased variables in pattern matching)
TAG : scala
Date : November 15 2020, 11:01 PM , By : Harun Madensoy
Initialize several objects at once
Initialize several objects at once
Any of those help I have a Type called Mark, and a 4 variables initialized to null. They are declared as:
TAG : scala
Date : November 14 2020, 11:01 PM , By : Diegatxo
How to do Multiple column count in SPARK/SCALA efficiently?
How to do Multiple column count in SPARK/SCALA efficiently?
To fix this issue I have a data frame from which I need counts of all the columns with filter (value > 0) for each column . , Define a list of columns:
TAG : scala
Date : November 13 2020, 11:01 PM , By : jlemon26
Asynchronous IO (socket) in Scala
Asynchronous IO (socket) in Scala
hop of those help? , Answer to Question 1She suggests two things
TAG : scala
Date : November 13 2020, 11:01 PM , By : Smokylicious
Scala and Hive: best way to write a generic method that works with all types of Writable
Scala and Hive: best way to write a generic method that works with all types of Writable
this one helps. Though not written in Scala, looking at generic UDAFs in hive itself such as GenericUDAFAverage or GenericUDAFHistogramNumeric, it seems they turn any primitive numeric input into Double (using PrimitiveObjectInspectorUtils.getDouble)
TAG : scala
Date : November 12 2020, 11:01 PM , By : abhishek ambure
Unable to make reference to object in build.sbt, "error: not found: value hooks"
Unable to make reference to object in build.sbt, "error: not found: value hooks"
seems to work fine I'm trying to add gulp to my Play application, I have created a PlayRunHook object that should allow me to trigger the gulp command, but when I do sbt run I'm getting an error saying it could not find the object. Here is my hook: ,
TAG : scala
Date : November 12 2020, 11:01 PM , By : Leping Wan
Process large text file using Zeppelin and Spark
Process large text file using Zeppelin and Spark
To fix the issue you can do I'm trying to analyze(visualize actually) some data from large text file(over 50 GB) using Zeppelin (scala). Examples from the web use csv files with known header and datatypes of each column. In my case, I have lines of a
TAG : scala
Date : November 12 2020, 11:01 PM , By : HRH SL RoA
value toArray is not a member of org.apache.spark.rdd.RDD[(String, Int)]
value toArray is not a member of org.apache.spark.rdd.RDD[(String, Int)]
To fix the issue you can do I have got a problem when I tired to compile my scala program. Here's my code. , Spark has mainly two types of Operations on RDD:
TAG : scala
Date : November 12 2020, 11:01 PM , By : Ed Lasher
What is wrong with the method definition
What is wrong with the method definition
fixed the issue. Will look into that further You are getting tripped up by the hidden (implicit) parameters to the accumulate method. The context bounds you've placed on it mean that the method really has the following type signature:
TAG : scala
Date : November 11 2020, 11:01 PM , By : Maxi Aznarez
Make CRUD operations with ReactiveMongo
Make CRUD operations with ReactiveMongo
will help you You are trying to call the insert operation on a Future[Collection], rather than on the underlying collection (calling operation on Future[T] rather than on T is not specific to ReactiveMongo).It's recommanded to have a look at the docu
TAG : scala
Date : November 11 2020, 11:01 PM , By : Harrison Bennett
Spark unable to find "spark-version-info.properties" when run from ammonite script
Spark unable to find "spark-version-info.properties" when run from ammonite script
it fixes the issue Following seems to work on 2.11 with 1.0.1 version but not experimental.Could be just better implemented on Spark 2.2
TAG : scala
Date : November 10 2020, 11:01 PM , By : Mohammed NasraAllah
Intersection of Two Map rdd's in Scala
Intersection of Two Map rdd's in Scala
wish of those help Since you are looking intersect on values, you need to join both RDDs, get all the matched values, then do the intersect on values.sample code:
TAG : scala
Date : November 09 2020, 11:01 PM , By : Alexander Miko
Spark - Scala : Return multiple <key, value> after processing one line
Spark - Scala : Return multiple <key, value> after processing one line
hop of those help? I have a dataset that looks like below - , Your problem can be solved like this :
TAG : scala
Date : November 09 2020, 11:01 PM , By : badrequest
Adding Scala Concurrent Duration To a DateTime
Adding Scala Concurrent Duration To a DateTime
like below fixes the issue You can accomplish this using an implicit class and which adds methods to LocalDateTime:
TAG : scala
Date : November 09 2020, 11:01 PM , By : Rodrigo
Why those two stages in apache spark are computing same thing?
Why those two stages in apache spark are computing same thing?
I wish this help you RDDs are cached first time it is computed in an action. The first action in your code is "distinct", that is when the "sparseFilter" RDD is cached. So the first cache operation may not be useful for the subsequent stages. The fir
TAG : scala
Date : November 09 2020, 11:01 PM , By : Nwit Tan
Using tuple as a key in scala
Using tuple as a key in scala
help you fix your problem Question 1: Can I use tuple as a key of a map in Scala? Question 2: If yes , how can I create a map with a tuple as key? , Yes, you can use Tuple as a key in Map.For example:
TAG : scala
Date : November 06 2020, 11:01 PM , By : drakevandome
writing SparkRDD to a HBase table using Scala
writing SparkRDD to a HBase table using Scala
this one helps. For example, the below method takes Int as argument and returns Double
TAG : scala
Date : November 05 2020, 11:01 PM , By : alekon
Could someone explain how is the this code executing?
Could someone explain how is the this code executing?
this one helps. R is a type variable. The definition def unmarshalJsValue[R](request: Request[JsValue])(block: R => Result)(implicit rds : Reads[R]) reads:
TAG : scala
Date : November 05 2020, 11:01 PM , By : Rachit
Datastax spark cassandra connector - writing DF to cassandra table
Datastax spark cassandra connector - writing DF to cassandra table
seems to work fine Using RDDs, spark-cassandra-connector automatically converts camel cased properties to underscored column names. again RussSHere is how I am saving case class objects to cassandra table
TAG : scala
Date : November 05 2020, 11:01 PM , By : bhavin
bigquery Repeated record added outside of an array
bigquery Repeated record added outside of an array
it fixes the issue Found the problem.It's something with scala-to-java collections conversions mess. I had to explicitly add the conversion using JavaConversions.seqAsJavaList and it magically started working
TAG : scala
Date : November 05 2020, 11:01 PM , By : Bou
Scala infinite iterate function
Scala infinite iterate function
may help you . I am trying to write in Scala a function similar to the Haskell "iterate" function. Given a value x and a function f, iterate should return a Stream composed of the values x, f(x), f(f(x)), etc... , I assume you need something like thi
TAG : scala
Date : November 04 2020, 04:05 PM , By : Woifi
How to include test dependencies in sbt-assembly jar?
How to include test dependencies in sbt-assembly jar?
I wish this help you I have left out a crucial part in the original build.sbt excerpt I posted above which turned out to be the cause of the issuse:
TAG : scala
Date : November 04 2020, 04:05 PM , By : jo mal
Does scala.collection.Seq.groupBy() function preserve the order?
Does scala.collection.Seq.groupBy() function preserve the order?
This might help you The behavior is documented:
TAG : scala
Date : November 04 2020, 04:05 PM , By : Madhu Naik
Akka Streams - How to keep materialized value of an auxiliary Sink in a Graph
Akka Streams - How to keep materialized value of an auxiliary Sink in a Graph
I wish did fix the issue. Answering my own question...Found it! The source of Flow.alsoToMat pointed me to exactly the logic I needed - to access the materialized value of an auxiliary graph (in my case auxSink), one has to import its shape into the
TAG : scala
Date : November 03 2020, 11:01 PM , By : Le Cras
How does circe parse a generic type object to Json?
How does circe parse a generic type object to Json?
I wish this help you Encoding and decoding in circe are provided by type classes, which means that you have to be able to prove at compile time that you have a type class instance for A if you want to encode (or decode) a value of type A.This means t
TAG : scala
Date : November 03 2020, 11:01 PM , By : Linda Sturgill
What is the combination of flatMap and filter?
What is the combination of flatMap and filter?
I wish this help you Well, if you're trying to filter while using flatMap you can easily do something like
TAG : scala
Date : November 02 2020, 11:01 PM , By : Dee kapoor
Task not Serializable error:Spark
Task not Serializable error:Spark
this will help I have an RDD of form (String,(Int,Iterable[String])). The integer value (which I call distance) is initially set to 10 for each entry in the RDD. Every element in the Iterable[String] has its own entry in this RDD where it serves as a
TAG : scala
Date : November 01 2020, 11:01 PM , By : Bhaumik Patel
Scala subtype parameter
Scala subtype parameter
I hope this helps you . Because Form[Project] is not a subclass of Form[Model]. So the compiler complains about incompatible type in overriding value.Form[T] is invariant. You can read the variance doc
TAG : scala
Date : November 01 2020, 01:04 PM , By : Adam K
Scala and dropWhile
Scala and dropWhile
hop of those help? Iterator.dropWhile will drop any value as long as it matches the provided predicate, and return the remainder of the iterator:
TAG : scala
Date : November 01 2020, 12:01 AM , By : user6058091
Scala Recursive Function with Future Return Type
Scala Recursive Function with Future Return Type
may help you . I am writing a recursive retry function in scala where I want to know if there was a runtime error with the future creation. If there is then future instantiation is retried. , How about this?
TAG : scala
Date : November 01 2020, 12:01 AM , By : Константин Анатольев
Sequences in Spark dataframe
Sequences in Spark dataframe
I wish this help you Edited to answer @Tim's comment + fix patterns of the type "AABE"Yep, using a window function helps, but I created an id to have an ordering:
TAG : scala
Date : November 01 2020, 12:01 AM , By : jimbob54
Type mismatch for function composition
Type mismatch for function composition
will help you This is the case because the compiler is having difficulty inferring the types properly, specifically inferring what A is. You can help him by placing A as the first argument and each function in a separate parameter list:
TAG : scala
Date : November 01 2020, 12:01 AM , By : FAhmed
Error while trying to Iterate over List of Strings
Error while trying to Iterate over List of Strings
hope this fix your issue I have an RDD of form (String,(Int,Iterable[String])). I am trying to check if the string "Bethan" is a part of the Iterable[String]. I wrote the following line in scala: , Convert to list:
TAG : scala
Date : November 01 2020, 12:01 AM , By : Алексей Кушнир
What does "case class extends trait" mean in Scala?
What does "case class extends trait" mean in Scala?
this one helps. I am understanding my existing project, few things I am not able to understand: , Step by step:
TAG : scala
Date : October 31 2020, 05:38 PM , By : Hector Mendez
Any string concatenation method in slick groupBy?
Any string concatenation method in slick groupBy?
like below fixes the issue Slick takes your Scala code and converts it to SQL, so anything you do in Slick must be supported by the underlying SQL. If you search for similar questions related to concatenating strings in SQL, you find some results on
TAG : scala
Date : October 31 2020, 09:54 AM , By : Денис Балыкин
How to count the number of occurences of an element with scala/spark?
How to count the number of occurences of an element with scala/spark?
Hope that helps First, Scala is a type-safe language and so is Spark's RDD API - so it's highly recommended to use the type system instead of going around it by "encoding" everything into Strings. So I'll suggest a solution that creates an RDD[(Strin
TAG : scala
Date : October 31 2020, 09:54 AM , By : Vicky
How to build a parse tree of simple expressions
How to build a parse tree of simple expressions
this will help I think term ~ opt(("+"|"-") ~ expr) couldn't reserve the order of +/- operations.
TAG : scala
Date : October 31 2020, 05:55 AM , By : Pooja
Spark filter and count big RDD multiple times
Spark filter and count big RDD multiple times
I hope this helps . You can use the convenient countByKey just for that - just swap the places in the input beforehand to make the numeric value the key:
TAG : scala
Date : October 31 2020, 05:55 AM , By : Shaikh Sadiq
Why can't concrete members be overridden with abstract ones in scala?
Why can't concrete members be overridden with abstract ones in scala?
hop of those help? According to Scala Spec, a concrete definition always overrides an abstract definition.
TAG : scala
Date : October 31 2020, 12:01 AM , By : Rivergoat
String + StringOps = functor?
String + StringOps = functor?
like below fixes the issue I assumed that map would return me just a scala.Predef.String rather than an IndexedSeq[String] since the definition of a functor is that it's shape/structure should remain the same.
TAG : scala
Date : October 30 2020, 12:01 AM , By : soumya
Akka remote: is it possible to work with classes from two differents app which don't have the same package name?
Akka remote: is it possible to work with classes from two differents app which don't have the same package name?
wish help you to fix your issue What you want would require a full classpath scan (what if there is a third mypackage3.A which has also the same SerialVersionUID? How does the JVM know that it has to deserialize mypackage1.A into another type?) and o
TAG : scala
Date : October 30 2020, 12:01 AM , By : Anand Khot
How to perform merge operation on spark Dataframe?
How to perform merge operation on spark Dataframe?
fixed the issue. Will look into that further If you don't want to provide the list of columns explicitly, you can map over the original DF's columns, something like:
TAG : scala
Date : October 29 2020, 12:01 AM , By : Ann.S
Converting command line argument key=value pair to Map in scala
Converting command line argument key=value pair to Map in scala
wish helps you you can just use toMap().However, converting from array to tuple is not quite trivial: How to convert an Array to a Tuple?
TAG : scala
Date : October 29 2020, 12:01 AM , By : weichengwu
Implement Actor model without Akka in Scala
Implement Actor model without Akka in Scala
I hope this helps . You can look at Actor model implementation in scalazand take ideas from it, source code in scalaz actor is easier for insight than akka. You have freedom of choice about architecture: you can use mailboxes based on ConcurrentLinke
TAG : scala
Date : October 29 2020, 12:01 AM , By : Lee
calling reduce on list of akka http routes yields compilation error (no implicit value for parameter join)
calling reduce on list of akka http routes yields compilation error (no implicit value for parameter join)
wish help you to fix your issue Your problem is that your routeDef list is actually heterogeneous, the compiler infers its type to be List[PathMatcher[_ >: Tuple1[String] with Unit]].Given that, the (a: PathMatcher[L])./(b: PathMatcher[R]) method nee
TAG : scala
Date : October 25 2020, 04:08 PM , By : Neof
Append/concatenate two RDDs of type Set in Apache Spark
Append/concatenate two RDDs of type Set in Apache Spark
wish of those help You are applying the union on a list (seq) of sets that is why the elements are the complete sets and not their elements. Try using:
TAG : scala
Date : October 25 2020, 04:08 PM , By : Hazem.sh

shadow
Privacy Policy - Terms - Contact Us © soohba.com