Recent questions tagged Scala

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scala - Spark 1.6: java.lang.IllegalArgumentException: spark.sql.execution.id is already set

I'm using spark 1.6 and run into the issue above when I run the following code: // Imports import ... doing something wrong / any workarounds? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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919 views

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scala - Find all implicits

Is there a way in Scala to find and display all uses of implicits in my code, or compile without implicits ... extra memory in inner loops. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.1k views

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scala - IntelliJ IDEA: Cannot import SBT project

I'm completely new to development using Play or IntelliJ for that matter. I've created a simple HelloWorld ... with the SBT plugin installed. 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 fails with java.lang.NoClassDefFoundError: sbt/ConsoleOut$

After using sbt for some time, something failed and I can't run sbt on my Ubuntu machine. I get this exception ... 13. Could this be related? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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999 views

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scala - How can I fix the missing implicit value for parameter ta: TildeArrow in a test spec

I'm working on a simple test spec using spray and I can't get it to compile correctly, don't know if ... ] route test.And MyProxy extends Actor See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.3k views

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scala - Spark : Read file only if the path exists

I am trying to read the files present at Sequence of Paths in scala. Below is the sample (pseudo) code: ... specific API to check the existence. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.4k views

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scala - error: expected class or object definition

I have this (smart code): import com.mongodb.casbah.Imports._ import com.mongodb.casbah.util.bson.conversions._ ... error message. Any ideas? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.2k views

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scala - How does | (pipe) in pattern matching work?

You can write: str match { case "foo" | "bar" => ... } At first glance it looks like | could be an ... but it's impossible to search for...) See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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916 views

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scala - load a local file to spark using sc.textFile()

Question How to load a file from the local file system to Spark using sc.textFile? Do I need to ... .SparkSubmit.main(SparkSubmit.scala) > See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.2k views

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scala - How to pass a list of paths to spark.read.load?

I can load multiple files at once by passing multiple paths to the load method, e.g. spark.read .format("com. ... of paths to the load method? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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984 views

1 answer

scala - launching a spark program using oozie workflow

I am working with a scala program using spark packages. Currently I run the program using the bash command from ... to the one appearing here? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.0k views

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scala - Akka HTTP 2.0 to use SSL (HTTPS)

I am trying to add a self signed certificate to my configuration in order to make my web service to serve content ... using akka 2.0 and scala See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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769 views

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scala - How to create a graph from Array[(Any, Any)] using Graph.fromEdgeTuples

I am very new to spark but I want to create a graph from relations that I get from a Hive table. I found ... I convert to the suitable format ? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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831 views

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scala - Can we able to use mulitple sparksessions to access two different Hive servers

I have a scenario to compare two different tables source and destination from two separate remote hive servers ... or SparkContext. 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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901 views

1 answer

scala - Play: additional public / assets directory

In order to have a clean directory structure, I would like to make an additional assets folder public. I've created ... more. What am I missing? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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828 views

1 answer

scala - When applying `map` to a `Set` you sometimes want the result not to be a set but overlook this

Or how to avoid accidental removal of duplicates when mapping a Set? This is a mistake I'm doing very often. ... Set?) and without touching it. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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838 views

1 answer

scala - Using Futures within Spark

A Spark job makes a remote web service for every element in an RDD. A simple implementation might look something ... to a Spark RDD. 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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928 views

1 answer

scala - Writing RDD partitions to individual parquet files in its own directory

I am struggling with step where I want to write each RDD partition to separate parquet file with its own directory. ... I am new to this stack. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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822 views

1 answer

scala - How to set default dependencies for all subprojects in SBT?

Trying to understand how to set up SBT subprojects. What is the correct way to set default dependencies for ... was just illustrating my point. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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940 views

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scala - Cannot override a type with non-volatile upper bound

I have a compiler error in scala and I don't know what does it refer to: Assume these declarations: trait Abstract ... , how to achieve my goal? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.0k views

1 answer

scala - Why future has side effects?

I am reading the book FPiS and on the page 107 the author says: We should note that Future doesn't ... has not purely functional interface? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.0k views

1 answer

scala - Type casting using type parameter

Given is a Java method that returns java.lang.Objects for a given string. I'd like to wrap this method in ... convert might have to be altered. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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967 views

1 answer

scala - How to run a sbt-managed application project without sbt?

My question is about running an application that's in a project managed by sbt 0.10.1 and hence relies on ... I run the application without sbt? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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973 views

1 answer

scala - Akka-http: Accept and Content-type handling

I'm trying out Akka-http and hopefully someone can shed light on a the following questions: How does one create ... . criticism very welcome. ;) See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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910 views

1 answer

scala - Why can't the first parameter list of a class be implicit?

scala> class A(implicit a: Int); defined class A scala> class B()(implicit a: Int); defined class B scala ... done. I find it rather surprising. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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892 views

1 answer

scala - Is it possible to alias columns programmatically in spark sql?

In spark SQL (perhaps only HiveQL) one can do: select sex, avg(age) as avg_age from humans group by sex ... releases and sql-context backends). See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

973 views

1 answer

scala - Merge Spark output CSV files with a single header

I want to create a data processing pipeline in AWS to eventually use the processed data for Machine Learning. I ... multiple times, not once. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.1k views

1 answer

scala - How to force SBT to use Java 8?

How can I force SBT to compile to Java 8 class files. I added scalacOptions += "-target:jvm-1.8" but it ... is required for this 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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