Questions tagged [scala]
Scala is a general-purpose programming language principally targeting the Java Virtual Machine. Designed to express common programming patterns in a concise, elegant, and type-safe way, it fuses both imperative and functional programming styles. Its key features are: an advanced static type system with type inference; function types; pattern-matching; implicit parameters and conversions; operator overloading; full interoperability with Java; concurrency
scala
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Output is not giving as Range(1,2,3,4) for val from1Until5 = 1 until 5 println(s"Range from 1 until 5 where 5 is excluded = $from1Until5")
I am executing
println("\nStep 2: Create a numeric range from 1 to 5 but excluding the last integer number 5")
val from1Until5 = 1 until 5
println(s"Range from 1 until 5 where 5 is ...
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1
answer
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nested case class generic filter method
I have some nested case classes that may look like the following:
case class Lowest(intVal: Int, stringVal: String)
case class Mid (lowestSeq: Seq[Lowest])
case class High (midSeq: Seq[Mid])
So if ...
- 538
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How to address the performance impact of executing multiple functions dynamically compiled with Scala 2's runtime reflection?
I have an entity that generates Scala functions compiled dynamically using Scala 2's runtime reflection. My case is slightly more convoluted, but the following showcases the issue:
import scala....
- 207
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Create Flow[ByteString, ByteString, NotUsed] by piping through InputStream
I need decompress data using compression not supported by akka, but supported by other library which provided InputStream interface.
To make it work with akka stream, I need to implement function:
def ...
- 23
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How to run MySQL scripts when I run docker compose? [duplicate]
I have a Scala backend and Javascript frontend applications and MySQL database. I want to create docker images for every one of them with one docker-compose.yml file and I want to run the scripts for ...
1
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22
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Scala 3 reflection: collect all members that are singleton objects
I have a method in Scala 2 that uses reflection. It doesn't work in Scala 3, and I would like to reimplement it so it works for Scala 3. (I will no longer need it for Scala 2 anymore, so it need not ...
- 6,113
1
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27
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Chisel Template Not Functioning Windows 11 - Cannot run program "which": CreateProcess error=2, The system cannot find the file specified
After having cloned the template project for Chisel (https://github.com/chipsalliance/chisel-template) I tried running sbt test, and I got the following error in the file /src/test/scala/gcd/GCDSpec:
&...
- 35
1
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1
answer
47
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multiple pattern matching on iteration
val subjectpairs = IndexedSeq((8,0),(3,4),(0,9),(6,1))
val priors = subjectpairs.map { case( f,_) => f}.filter{ _ >0.0}
val posts = subjectpairs.map { case( _,l) => l}.filter{ _ >0.0}
...
- 9,645
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Encrypt Spark Libsvm Dataframe
I have a libsvm file that I want to load into Spark and then encrypt it. I want to iterate over every element in the features to apply my encrypt function, but there doesn't seem to be any way to ...
- 41
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Adding new Rows to Spark Partition while using forEachPartition
I am trying to add a new Row to each Partition in my Spark Job. I am using the following code to achieve this:
StructType rowType = new StructType();
rowType.add(DataTypes.createStructField("...
- 1,081
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IntelliJ Scala warning with parameterized type in compiled JAR
I have Scala code with parameterized types like this:
val foo: SomeParameterizedType[_ <: Product with Serializable] =
new SomeParameterizedType[Foo](arguments)
val bar: SomeParameterizedType[_ &...
- 18.5k
1
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0
answers
28
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Unable to connect to MongoDB replicaset from scala mongodb driver
I am running mongodb replicaset in docker on localhost and I am able to connect to it from both command line and Mongodb Compass. When I try to connect from code I get Connection Refused. I am unable ...
- 5,036
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28
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Scala can't find imported file from same directory
I'm fairly new to scala, having troubles compiling my code. So I have a project structure like this
topdir/
com/
name/
final/
file1.scala
file2.scala
Both files are in the same package ...
- 103
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IntelliJ Scala 2.13.0 no longer compiles - Error compiling the sbt component 'compiler-bridge-2.13.0-66.0'
I am working on a hobby project on my desktop using Scala 2.13.0 and JDK 22. The project compiles and runs perfectly fine there. This project is also on my personal GitHub. Because I went on holiday ...
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Scala Spark Dataframe creation from Seq of tuples doesn't work in Scala 3, but does in Scala 2
When trying to test something locally with Scala Spark, I noticed the following problem and was wondering what causes it, and whether there exists a workaround.
Consider the following build ...
- 718