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scala - An easy way to get rid of *everything* generated by SBT?
    Is there an easy way to get rid of everything getting generated as a result of performing an SBT build? It turns ... doesn't get rid of all. See Question&Answers more detail:os...
asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)
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833 views
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scala - How to see dependency tree in sbt?
    I am trying to inspect the SBT dependency tree as described in the documentation: sbt inspect tree clean But I get ... 't SBT build the tree? See Question&Answers more detail:os...
asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)
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549 views
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scala - Getting a structural type with an anonymous class's methods from a macro
    Suppose we want to write a macro that defines an anonymous class with some type members or methods, and then creates ... on it) from a macro? See Question&Answers more detail:os...
asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)
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609 views
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scala - How to have Eclipse recognize dependencies from SBT
    I am trying to figure out how to make Eclipse recognize dependencies that are retrieved using SBT? SBT download the ... way to do this? thanks See Question&Answers more detail:os...
asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)
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503 views
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scala - Functional Programming - Lots of emphasis on recursion, why?
    I am getting introduced to Functional Programming [FP] (using Scala). One thing that is coming out from my ... doing iterative stuff as well. See Question&Answers more detail:os...
asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)
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883 views
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scala - Tuple Unpacking in Map Operations
    I frequently find myself working with Lists, Seqs, and Iterators of Tuples and would like to do something like the ... can I get around this? See Question&Answers more detail:os...
asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)
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974 views
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scala - How to convert an Int to a String of a given length with leading zeros to align?
    How can I convert an Int to a 7-character long String, so that 123 is turned into "0000123"? See Question&Answers more detail:os...
asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)
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16.0k views
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scala - Creating a flow from actor in Akka Streams
    It's possible to create sources and sinks from actors using Source.actorPublisher() and Sink.actorSubscriber() methods ... 2.4.9) version. See Question&Answers more detail:os...
asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)
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scala - SBT Test-Dependencies in Multiprojects: Make the Test-Code Available to Dependent Projects
    I've a SBT multi-project where some projects have dependencies to each other. Like this: lazy val coreProject: ... of the 'exension'-project? See Question&Answers more detail:os...
asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)
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724 views
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scala 2.10 - IntelliJ IDEA Report Highlighting error when using routes in Controller
    I have a Scala Play project. I'm using Play 2.2.1. I downloaded Scala, Play 2 supported and SBT ... remains "Unspecified value parametrs" error. See Question&Answers more detail:os...
asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)
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601 views
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scala - Akka HTTP: Blocking in a future blocks the server
    I am trying to use Akka HTTP to basic authenticate my request. It so happens that I have an external ... without blocking my entire API? See Question&Answers more detail:os...
asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)
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750 views
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scala - Calculating the Moving Average of a List
    This weekend I decided to try my hand at some Scala and Clojure. I'm proficient with object oriented ... how to express that functionally. See Question&Answers more detail:os...
asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)
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573 views
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scala - Pattern matching with conjunctions (PatternA AND PatternB)
    Scala has a language feature to support disjunctions in pattern matching ('Pattern Alternatives'): x match { case _: ... true && false && true`. See Question&Answers more detail:os...
asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)
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555 views
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scala - Pass implicit parameter through multiple objects
    I wonder is it possible to pass implicit params through singletons like that case class Greet(g: String) object Foo { ... but in outer of it? See Question&Answers more detail:os...
asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)
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836 views
1 answer
scala - How to save RDD data into json files, not folders
    I am receiving the streaming data myDStream (DStream[String]) that I want to save in S3 (basically, for this ... -"+datetimeString+".json") } See Question&Answers more detail:os...
asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)
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670 views
1 answer
scala - Why Akka streams cycle doesn't end in this graph?
    I would like to create a graph that loop n times before going to sink. I've just created this sample that fulfill ... .shutdown() } } } }` See Question&Answers more detail:os...
asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)
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707 views
1 answer
scala - Why asInstanceOf doesn't throw a ClassCastException?
    Why asInstanceOf doesn't throw a ClassCastException ? scala> List("a").asInstanceOf[List[Int]] res34: List[Int] = List(a) See Question&Answers more detail:os...
asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)
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718 views
1 answer
scala - SBT 0.13.11 cannot download dependencies behind a proxy
    Using Windows 7, 64bit, behind a proxy server. I have downloaded and installed the latest versions of SBT(0. ... I receive the following output: See Question&Answers more detail:os...
asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)
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720 views
1 answer
scala - Apache Spark : When not to use mapPartition and foreachPartition?
    I know that when we want to initialize some resource for a group of RDDs instead of individual RDD elements ... () transformation and action. See Question&Answers more detail:os...
asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)
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767 views
1 answer
scala - Flaky onSuccess of Future.sequence
    I wrote this method: import scala.concurrent._ import ExecutionContext.Implicits.global import scala.util.{ Success, ... not work as expected. See Question&Answers more detail:os...
asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)
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727 views
1 answer
scala - Execution context without daemon threads for futures
    I am having trouble with the JVM immediately exiting using various new applications I wrote which spawn threads ... on non-daemon threads? See Question&Answers more detail:os...
asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)
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539 views
1 answer
scala - SBT dependsOn RootProject: doesn't compile the dependency
    I have a pretty simple configuration: //lazy val bananaRdfProject = RootProject( uri("git://github.com:stample/ ... on an external RootProject? See Question&Answers more detail:os...
asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)
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669 views
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scala - How to use LEFT and RIGHT keyword in SPARK SQL
    I am new to spark SQL, In MS SQL, we have LEFT keyword, LEFT(Columnname,1) in('D','A') then 1 else 0. How to implement the same in SPARK SQL. See Question&Answers more detail:os...
asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)
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486 views
1 answer
scala - How can I differentiate between def foo[A](xs: A*) and def foo[A, B](xs: (A, B)*)?
    I know that type erasure makes them look equal, type-wise, at runtime, so that: class Bar { def foo[A](xs: A*) { ... .fooPairs(1 -> 2, 3 -> 4) See Question&Answers more detail:os...
asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)
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1.3k views
1 answer
scala - Suppress "discarded non-Unit value" warning
    I have added the scalac command line argument -Ywarn-value-discard to my build because this would have caught ... do I suppress those warnings? See Question&Answers more detail:os...
asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)
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607 views
1 answer
scala - How to filter Spark dataframe if one column is a member of another column
    I have a dataframe with two columns(one string and one array of string): root |-- user: string (nullable = true ... rows that user is in users? See Question&Answers more detail:os...
asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)
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982 views
1 answer
scala - How to read a zip containing multiple files in Apache Spark
    I am having a Zipped file containing multiple text files. I want to read each of the file and build a List of RDD ... urls[-1].split('_')[0] See Question&Answers more detail:os...
asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)
0 votes
672 views
1 answer
scala - Why are scaladoc method signatures wrong?
    There are a lot of places in the Scala API, particularly in collections, where method signatures are wrong. For ... here? Is this a mistake? See Question&Answers more detail:os...
asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)
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