scala Questions
8
Solved
Scala has direct support for using hex and octal numbers:
scala> 01267 + 0100
res1: Int = 759
scala> 0x12AF + 0x100
res2: Int = 5039
but how do you do express an integer as a binary numbe...
2
Solved
Suppose that I have some typeclass
trait FooBar[X]
and an instance of FooBar[Int]:
given intIsFooBar: FooBar[Int] = new FooBar {}
Now, suppose that I have an interface Intf that has some member t...
Virgil asked 21/3, 2023 at 21:31
5
Solved
In Akka, is there a way to restrict messages to actors to be of a specific static type other than using the "Typed Actor" APIs that use an RPC style programming model?
Can I use the message passin...
2
Solved
I'm having some trouble encoding data when some columns that are of type Option[Seq[String]] are missing from our data source. Ideally I would like the missing column data to be filled with None.
...
Dutra asked 3/1, 2017 at 23:50
3
Is there any way to get the number of records written when using spark to save records? While I know it isn't in the spec currently, I'd like to be able to do something like:
val count = df.write....
Ulita asked 12/5, 2017 at 9:30
13
Solved
Below the steps I did to get this issue :
Launch ZooKeeper
Launch Kafka : .\bin\windows\kafka-server-start.bat .\config\server.properties
And at the second step the error happens :
ERROR F...
Melda asked 25/12, 2019 at 21:10
5
Solved
I have evolution problem Unknown data type: "JSONB" when running tests in playframework using
playframework v2.6.6 for scala
play-slick v3.0.2
play-slick-evolutions v3.0.2
postgresql - 42.0.0
h2...
Floorman asked 21/12, 2017 at 11:53
4
Solved
I need a Support Vector Machine library for Scala.
I guess that I should have a look at both Scala and Java implementations, do you recommend me to use any of them in particular?
Billetdoux asked 21/9, 2012 at 18:59
1
I am trying to use spark cassandra connector to fetch values from the table. The load() yields the IncompatibleClassChangeError. My development environment is defined as follows,
Intellij : 2019.3....
Albumin asked 30/1, 2020 at 12:24
2
I need to know the fileName for the input file that is streamed from the input dir.
Below is the spark FileStreaming code in scala programming
object FileStreamExample {
def main(args: Array[St...
Chairborne asked 13/10, 2019 at 9:42
4
Solved
I have a dataframe df with the following schema:
root
|-- city_name: string (nullable = true)
|-- person: struct (nullable = true)
| |-- age: long (nullable = true)
| |-- name: string (nullabl...
Villainage asked 1/3, 2018 at 9:49
3
Solved
I'm getting the error message
java.lang.IllegalArgumentException: Schema must be specified when creating a streaming source DataFrame. If some files already exist in the directory, then depending o...
Postfree asked 17/10, 2021 at 19:56
4
Solved
contains like functionality for play.api.libs.json.Json
val data=Map("id" -> "240190", "password" -> "password","email" -> "[email protected]")
data.contains("email")//true
val in...
Emeldaemelen asked 23/7, 2014 at 7:35
4
I am writing my own simple javax.sql.DataSource implementation, the only method of it I need to work is getConnection: Connection, but the interface inherits many other methods (which I don't need)...
2
Solved
I would like to chain http request using akka-http-client as Stream. Each http request in a chain depends on a success/response of a previous requests and uses it to construct a new request. If a r...
Anschauung asked 11/9, 2016 at 15:31
4
Solved
Does anyone know how to show a custom failure message in ScalaTest?
For example:
NumberOfElements() should equal (5)
Shows the following message when it fails:
10 did not equal 5
But i wan...
11
I want to create on DataFrame with a specified schema in Scala. I have tried to use JSON read (I mean reading empty file) but I don't think that's the best practice.
Bathyal asked 17/7, 2015 at 13:58
4
Solved
I wonder how to get a class object for an object type in Scala. Ok, that is a mouth full because of the double meaning for object. So here an example which will fail:
object Main
{
private [this]...
Radices asked 9/3, 2012 at 14:21
8
Solved
I'm a newbie to scala, I'm just writing a simple function to reverse a given string:
def reverse(s: String) : String
for(i <- s.length - 1 to 0) yield s(i)
the yield gives back a scala.colle...
Hornbeam asked 8/10, 2011 at 23:20
4
Solved
What is the suitable way to compute hashCode of an Array that depends on its content?
Array.hashCode is for the array instance:
val h = a.hashCode
println(h == Array(1,2).hashCode) // false
a(0)...
2
Solved
I found myself lately using sliding(n,n) when I need to iterate collections in groups of n elements without re-processing any of them. I was wondering if it would be more correct to iterate those c...
Meadors asked 30/9, 2015 at 19:47
7
I am trying to compile Scala project which contains scalatest.
It compiles normal on sbt
sbt
> compile
> test:compile
, but when I am trying to build it with IDEA, it shows the following ...
Calceiform asked 1/10, 2016 at 22:27
4
Solved
Why and how specifically is a Scala Future not a Monad; and would someone please compare it to something that is a Monad, like an Option?
The reason I'm asking is Daniel Westheide's The Neophyte's...
4
I'm trying to call the Selenium Java libraries from Scala. I'm using Scala IDE (Eclipse), and Scala 2.10.2. What is causing this compiler error?
error while loading Function, class file '/Dev/sele...
Brahma asked 3/9, 2013 at 19:15
4
Solved
I'm trying to generate a UUID with all zeros:
java.util.UUID fromString "00000000-00000000-00000000-00000000"
The error is
java.lang.IllegalArgumentException: Invalid UUID string: 00000000-000...
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