scala

What is a simple way to define a string constant to be the contents of a file at compile-time (in Scala)?

由 拥有回忆 提交于 2021-02-19 06:38:04
问题 I would like to define a Scala val to be a String whose value is the entire contents of a text file, as read at compile time . So, after compilation, this should just behave as a string constant. I have the feeling that this should be simple with, e.g., Scala macros, but so far I couldn't work out how to get the String value out simply. 回答1: You could make an sbt source generation task that executes at compile time; here's a simple example copied from those docs. It wouldn't be hard to extend

java.lang.NoSuchMethodException: scala.collection.immutable.$colon$colon

由 你离开我真会死。 提交于 2021-02-19 06:30:55
问题 I am trying to call a function using a variable as String type dynamically i.e. variable will contain a function name as String. So, I need to call a function using that variable. So, I am using Scala Reflection. It is working if the function is accepting datatype as Sting, But it is throwing error List[Map[String, Double]] I used below link to refer a code Is there any Scala feature that allows you to call a method whose name is stored in a string? and below is a test program which I am

Circe Decode to sealed trait extended by multiple case classes

由 ＊爱你＆永不变心＊ 提交于 2021-02-19 06:28:06
问题 I've seen similar questions before, but none of them have worked. I think that they ask something different so I'm asking here. I have something like this in one file: sealed trait Thing case class SomeThing() extends Thing case class OtherThing() extends Thing and in another file: val str = //valid json val decoded = decode[Thing](str) println(decoded) and I get: Left(DecodingFailure(...)) This works if I did: val str = //valid json val decoded = decode[SomeThing](str) println(decoded) 回答1:

How to add Scala compiler plugin only for test sources

由 核能气质少年 提交于 2021-02-19 06:14:58
问题 Is it possible to add a Scala compiler plugin only when compiling test sources? When a compiler plugin is added by calling SBT's addCompilerPlugin then a library dependency is added. The relevant methods are: /** Transforms `dependency` to be in the auto-compiler plugin configuration. */ def compilerPlugin(dependency: ModuleID): ModuleID = dependency.withConfigurations(Some("plugin->default(compile)")) /** Adds `dependency` to `libraryDependencies` in the auto-compiler plugin configuration. *

How to add Scala compiler plugin only for test sources

由 江枫思渺然 提交于 2021-02-19 06:14:34
问题 Is it possible to add a Scala compiler plugin only when compiling test sources? When a compiler plugin is added by calling SBT's addCompilerPlugin then a library dependency is added. The relevant methods are: /** Transforms `dependency` to be in the auto-compiler plugin configuration. */ def compilerPlugin(dependency: ModuleID): ModuleID = dependency.withConfigurations(Some("plugin->default(compile)")) /** Adds `dependency` to `libraryDependencies` in the auto-compiler plugin configuration. *

How to add Scala compiler plugin only for test sources

由 ≯℡__Kan透↙ 提交于 2021-02-19 06:14:15
问题 Is it possible to add a Scala compiler plugin only when compiling test sources? When a compiler plugin is added by calling SBT's addCompilerPlugin then a library dependency is added. The relevant methods are: /** Transforms `dependency` to be in the auto-compiler plugin configuration. */ def compilerPlugin(dependency: ModuleID): ModuleID = dependency.withConfigurations(Some("plugin->default(compile)")) /** Adds `dependency` to `libraryDependencies` in the auto-compiler plugin configuration. *

Why am i getting Unresolved dependencies path: org.scala-sbt:compiler-bridge_2.12:1.0.3

由 自闭症网瘾萝莉.ら 提交于 2021-02-19 05:59:24
问题 I'm trying to start project in intelij idea by this tutorial, but when i'm running my project i'm getting this warn and error Here's logs: [info] Loading settings from idea.sbt ... [info] Loading global plugins from /root/.sbt/1.0/plugins [info] Updating {file:/root/.sbt/1.0/plugins/}global-plugins... Waiting for lock on /root/.ivy2/.sbt.ivy.lock to be available... [info] Done updating. [info] Loading settings from plugins.sbt ... [info] Loading project definition from /home/r/Документы

Spark 学习（四）RDD自定义分区和缓存

由 爷，独闯天下 提交于 2021-02-19 05:52:01
一，简介 二，自定义分区规则 　　2.1 普通的分组TopN实现 　　2.2 自定义分区规则TopN实现 三，RDD的缓存 　　3.1 RDD缓存简介 　　3.2 RDD缓存方式 正文 一，简介 　　 在之前的文章中，我们知道RDD的有一个特征：就是一组分片（Partition），即数据集的基本组成单位。对于RDD来说，每个分片都会被一个计算任务处理，并决定并行计算的粒度。用户可以在创建RDD时指定RDD的分片个数，如果没有指定，那么就会采用默认值。默认值就是程序所分配到的CPU Core的数目。这个分配的规则我们是可以自己定制的。同时我们一直在讨论Spark快，快的方式有那些方面可以体现，RDD缓存就是其中的一个形式，这里将对这两者进行介绍。 二，自定义分区规则 　　分 组求TopN的方式有多种，这里进行简单的几种。这里尊卑一些数据： 点击下载 　　2.1 普通的分组TopN实现 　 　实现思路一：先对数据进行处理，然后聚合。最后进行分组排序。 package cn.edu360.sparkTwo import org.apache.spark.rdd.RDD import org.apache.spark.{SparkConf, SparkContext} object SubjectTopNone { def main(args: Array[String]): Unit =

Scala sbt file dependency from github repository

由 浪尽此生 提交于 2021-02-19 05:20:14
问题 Is it possible to include a dependency from github? The repository does not have a jar file, just a build.sbt file and a source folder. 回答1: You can create a new project which points to the source in your build.sbt and then use dependsOn : lazy val projectIDependOn = RootProject(uri("git://github.com/user/Project.git")) lazy val myProject = project in file("my-project").dependsOn(projectIDependOn) An alternative approach would be to clone to github repository and then use sbt-assembly to

Scala sbt file dependency from github repository

由 断了今生、忘了曾经 提交于 2021-02-19 05:20:13
问题 Is it possible to include a dependency from github? The repository does not have a jar file, just a build.sbt file and a source folder. 回答1: You can create a new project which points to the source in your build.sbt and then use dependsOn : lazy val projectIDependOn = RootProject(uri("git://github.com/user/Project.git")) lazy val myProject = project in file("my-project").dependsOn(projectIDependOn) An alternative approach would be to clone to github repository and then use sbt-assembly to
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