All Scala Solutions on Gang of Coders

Total of 677 Scala Solutions

Difference between == and === in Scala, Spark

Scala Apache Spark

Advantages of Scala's type system

The type system in Scala is Turing complete. Proof? Example? Benefits?

Language Agnostic Scala Type Systems Turing Complete

How can colored terminal output be disabled for sbt/play?

Scala Playframework Sbt

Functions vs methods in Scala

How to split strings into characters in Scala

String Scala Character Encoding Split Character

What's the status of Scala.React?

scala: How to pass an expanded list as varargs into a method?

Scala Map Variadic Functions

Why does a small change to this Scala code make such a huge difference to performance?

Performance Optimization Scala

Why are Arrays invariant, but Lists covariant?

Arrays List Scala Covariance

Declare variable in a Play2 scala template

Html Scala Templates Playframework Playframework 2.0

In Scala, how to get a slice of a list from nth element to the end of the list without knowing the length?

Scala - how to print case classes like (pretty printed) tree

Scala Pretty Print Case Class

How to cancel Future in Scala?

Multithreading Scala Future

Is there a generic way to memoize in Scala?

Scala Scope Dynamic Programming Memoization Forward Reference

Google Maps API v2 SupportMapFragment inside ScrollView - users cannot scroll the map vertically

Android Scala Google Maps-Android-Api-2

Why does Spark fail with java.lang.OutOfMemoryError: GC overhead limit exceeded?

Scala Apache Spark

How to model type-safe enum types?

Get field names list from case class

Converting Java to Scala durations

Scala Config Duration Scala Java-Interop

Automatically and Elegantly flatten DataFrame in Spark SQL

Scala Apache Spark Apache Spark-Sql

Functional Reactive Programming in Scala

Scala Functional Programming

"eval" in Scala

Java Scala Scripting Embedding

Is this the proper way to initialize null references in Scala?

Is there a brief syntax for executing a block n times in Scala?

How to append or prepend on a Scala mutable.Seq

Scala Sequence Scala Collections Mutable

Valid identifier characters in Scala

Scala Operators

Immutable Scala Map implementation that preserves insertion order

Scala Dictionary Collections Immutability

Should I use Unit or leave out the return type for my scala method?

Scala Void Return Type

What is the relation between Iterable and Iterator?

Fold and foldLeft method difference

Cross product in Scala

Scala Functional Programming Cartesian Product Cross Product

IntelliJ Idea 12 + Android + Scala nowadays

Android Scala Ubuntu Ide Intellij Idea

What does the term "reason about" mean in computer science?

Scala Haskell Functional Programming

Difference in message-passing model of Akka and Vert.x

Scala Akka vert.x

In Scala, difference between final val and val

Scala Immutability

What's the difference between raw string interpolation and triple quotes in scala

String Scala String Interpolation

Is Future in Scala a monad?

Unit testing Scala

Unit Testing Scala Tdd

How can I construct and parse a JSON string in Scala / Lift

Json Scala Lift

Using varargs from Scala

Scala Variadic Functions

Scala: How do I dynamically instantiate an object and invoke a method using reflection?

Reflection Scala Name Mangling

The cost of nested methods

What are views for collections and when would you want to use them?

Scala Views Scala Collections

Disadvantages of Scala type system versus Haskell?

Scala Haskell Type Systems Static Typing Language Comparisons

for expressions versus foreach in Scala

Scala Loops Foreach

What is the rule for parenthesis in Scala method invocation?

Is Scala idiomatic coding style just a cool trap for writing inefficient code?

Scala Performance

What is the difference between def foo = {} and def foo() = {} in Scala?

Scala Programming Languages Functional Programming Jvm Jvm Languages

Usefulness (as in practical applications) of Currying v.s. Partial Application in Scala

Scala Partial Currying

Chart of IEnumerable LINQ equivalents in Scala?

C#Linq Scala Ienumerable Iterable

How to have Eclipse recognize dependencies from SBT

Eclipse Scala Sbt Sbteclipse

scala, guidelines on return type - when prefer seq, iterable, traversable

How to set a String in a Option[String]?

How to read a text file with mixed encodings in Scala or Java?

Java Scala Utf 8 Character Encoding Weka

Hidden performance cost in Scala?

Java Performance Scala Jvm Microbenchmark

How do I detect if a Spark DataFrame has a column

Scala Apache Spark Dataframe Apache Spark-Sql

Spark unionAll multiple dataframes

Scala Apache Spark Apache Spark-Sql

Custom Exception in scala

Scala Exception

Using Either to process failures in Scala code

Scala Functional Programming Either

Increase JVM heap size for Scala?

Scala Command Line Jvm Heap Memory

How to apply a function to a tuple?

Functional programming, Scala map and fold left

Scala Map Functional Programming Fold

How to choose a random element from an array in Scala?

Scala Scala 2.8

Scala reference equality

Scala - can a lambda parameter match a tuple?

Empty partial function in Scala

Scala Partialfunction

Scala: join an iterable of strings

Summing values in a List

Accessing value returned by scala futures

When to use case class or regular class

Explain the aggregate functionality in Spark (with Python and Scala)

Python Scala Apache Spark Aggregate Rdd

scala.concurrent.blocking - what does it actually do?

Scala Concurrency java.util.concurrent

Append a column to Data Frame in Apache Spark 1.3

Scala Apache Spark Dataframe

How to wait for N seconds between statements in Scala?

java.lang.NoSuchMethodError: scala.Predef$.refArrayOps

Including null values in an Apache Spark Join

Sql Scala Apache Spark Join Apache Spark-Sql

How are coroutines implemented in JVM langs without JVM support?

Java Scala Jvm Kotlin Jvm Languages

why is the lift web framework scalable?

Web Services Scala Frameworks Lift

Is the Lift framework as "easy" as Ruby on Rails or Django?

Ruby on-Rails Django Scala Lift

Scala: How to define "generic" function parameters?

Scala Haskell Polymorphism Type Inference

Different Scala Actor Implementations Overview

Scala Actor Lift Scalaz Akka

What is a higher kinded type in Scala?

Scala Generics Types Higher Kinded-Types Type Constructor

What is the difference between = and := in Scala?

Scala Syntax Colon Equals

Scala - Get last two characters from string

Typesafe config: Load additional config from path external to packaged scala application

Scala Configuration App Config Config Typesafe Stack

How do I break out of a loop in Scala?

Scala For Loop Break Tail Recursion

Print the data in ResultSet along with column names

Java Mysql Scala Jdbc

How to convert Row of a Scala DataFrame into case class most efficiently?

Scala Apache Spark Apache Spark-Sql

DataFrame equality in Apache Spark

Scala Apache Spark Dataframe Apache Spark-Sql Rdd

How do I check for equality using Spark Dataframe without SQL Query?

Scala Apache Spark Dataframe Apache Spark-Sql

Derive multiple columns from a single column in a Spark DataFrame

Scala Apache Spark Dataframe Apache Spark-Sql User Defined-Functions

What types are special to the Scala compiler?

covariant type A occurs in contravariant position in type A of value a

Code Coverage Tools for Scala

Unit Testing Scala Continuous Integration Hudson Code Coverage

How to reload a class or package in Scala REPL?

Scala Read Eval-Print-Loop

What are the differences between asInstanceOf[T] and (o: T) in Scala?

Is it possible to have tuple assignment to variables in Scala?

Scala Variable Assignment Tuples

How to reduce Seq[Either[A,B]] to Either[A,Seq[B]]?

Scala Functional Programming Scalaz Scala Cats

Why doesn't Scala have static members inside a class?

Class Scala Static Language Design Static Members

Scala Map foreach

Scala Scala Collections

Scala - mutable (var) method parameter reference

Scala Variables Methods Parameters

How to find if a Scala String is parseable as a Double or not?

Why couldn't twitter scale by adding servers the way sites like facebook have?

Ruby on-Rails Ruby Scala Twitter

What is the === (triple-equals) operator in Scala Koans?

Scala Scalatest Scala 2.9

How to exclude commons-logging from a scala/sbt/slf4j project?

Scala Sbt Slf4j

How to reference external sbt project from another sbt project?

Throwing exceptions in Scala, what is the "official rule"

Scala Exception Try Catch Either

Filtering a Scala List by type

values, types, kinds,... as an infinite sequence?

Scala Haskell Functional Programming Higher Kinded-Types

Clarification needed about futures and promises in Scala

Can't prove that singleton types are singleton types while generating type class instance

Scala Shapeless Implicits Singleton Type

+- Signs in Generic Declaration in Scala

How to fully clean, re-resolve and rebuild a Scala sbt-managed project in IDEA?

Scala Intellij Idea Sbt

dataframe: how to groupBy/count then filter on count in Scala

Scala Apache Spark Apache Spark-Sql

How to open SBT Tool Window in Intellij?

Scala Intellij Idea Sbt

-Ywarn-unused-import triggering on play routes file

Scala Playframework Sbt Scalac

What's the difference between join and cogroup in Apache Spark

Scala Apache Spark

Can a range be matched in Scala?

Scala Pattern Matching Range Matching

Use-cases for Streams in Scala

Scala Stream Scala Collections

Function syntax puzzler in scalaz

Scala Functional Programming Scala 2.8 Scalaz

Why aren't static methods considered good OO practice?

Java Scala Oop Static Methods Language Concepts

What is a function literal in Scala?

Scala Functional Programming

Comparing collection contents with ScalaTest

Unit Testing Scala Scalatest

Count all occurrences of a char within a string

Scala Divide two integers and get a float result

Scala Casting Floating Point Integer

Scala forall example?

scala class constructor parameters

Scala Constructor Scope Immutability

Scala : fold vs foldLeft

Scala Reduce Fold

Output path is shared between the same module error

Scala Maven Intellij Idea

How to get around the Scala case class limit of 22 fields?

Scala Case Class

Scala import not working - object <name> is not a member of package, sbt preppends current package namespace in imports

Unexpected implicit resolution based on inference from return type

Scala Type Inference Implicit Return Type Scalaz

Spark read file from S3 using sc.textFile ("s3n://...)

Java Scala Apache Spark Rdd Hortonworks Data-Platform

Creating a jar file from a Scala file

What's the best Scala build system?

Eclipse Scala Build

Scala profiler?

How do I exclude/rename some classes from import in Scala?

Scala Scala 2.8

Operator precedence in Scala

Scala Operator Precedence

Infinite streams in Scala

Idiomatic way to update value in a Map based on previous value

Scala Map Immutability

Scala filter on two conditions

Arrays Scala Filter Multiple Conditions

String interpolation in Scala 2.10 - How to interpolate a String variable?

Scala Scala 2.10 String Interpolation

Play Framework 2.1 - Cannot find an implicit ExecutionContext

Scala Playframework Playframework 2.0

How do I convert csv file to rdd

Scala Apache Spark

What are Scala context and view bounds?

Scala Implicits

Fetching distinct values on a column using Spark DataFrame

Scala Apache Spark Dataframe Apache Spark-Sql Spark Dataframe

What is "lifting" in Scala?

Function Scala Functional Programming Lifting

How to use Shapeless in a Quasiquote?

Scala Scala Macros Shapeless Scala Quasiquotes

Difference between method and function in Scala

Function Scala Methods

What does a lazy val do?

Scala Lazy Evaluation

Scala: Abstract types vs generics

Generics Scala Abstract Type

Scala Programming for Android

Android Scala Resources

Best way to parse command-line parameters?

Scala Command Line Command Line-Arguments

Call by name vs call by value in Scala, clarification needed

Appending an element to the end of a list in Scala

Case objects vs Enumerations in Scala

Scala Enumeration Case Class

Difference between case object and object

Task not serializable: java.io.NotSerializableException when calling function outside closure only on classes not objects

Scala Apache Spark Serialization

What is the difference between "def" and "val" to define a function

Get item in the list in Scala?

Scala 2.8 breakOut

Scala Scala 2.8 Scala Collections

How to clone a case class instance and change just one field in Scala?

How to get started with Akka Streams?

Scala Akka Stream

Akka Kill vs. Stop vs. Poison Pill?

Good scalaz introduction

What does `:_*` (colon underscore star) do in Scala?

Scala Pattern Matching

difference between foldLeft and reduceLeft in Scala

Scala Functional Programming Fold Higher Order-Functions

When should I choose Vector in Scala?

Scala Vector Scala Collections

What do <:<, <%<, and =:= mean in Scala 2.8, and where are they documented?

Scala Scala 2.8 Type Constraints

What is the difference between JavaConverters and JavaConversions in Scala?

Scala Scala Collections Scala Java-Interop

Spark performance for Scala vs Python

Scala Performance Apache Spark Pyspark Rdd

How do I cast a variable in Scala?

Reduce, fold or scan (Left/Right)?

Scala Scala Collections Reduce Fold

Is the Scala 2.8 collections library a case of "the longest suicide note in history"?

Scala Scala 2.8 Scala Collections

What Scala web-frameworks are available?

Scala Frameworks Web Frameworks Lift

Add JAR files to a Spark job - spark-submit

Java Scala Apache Spark Jar Spark Submit

How to define "type disjunction" (union types)?

(Why) do we need to call cache or persist on a RDD

Scala Apache Spark Rdd

Scala equivalent of Java java.lang.Class<T> Object

Java Class Scala

ScalaTest in sbt: is there a way to run a single test without tags?

Scala Testing Sbt Scalatest

Best way to merge two maps and sum the values of same key?

Scala Map Merge

How to select the first row of each group?

Sql Scala Apache Spark Dataframe Apache Spark-Sql

Getting a structural type with an anonymous class's methods from a macro

Scala Macros Scala 2.10 Structural Typing Scala Macros

Logging in Scala

Build.scala, % and %% symbols meaning

Scala Sbt Playframework 2.1

How can I change column types in Spark SQL's DataFrame?

Scala Apache Spark Apache Spark-Sql

Scala best way of turning a Collection into a Map-by-key?

Scala Map Scala Collections

Is asynchronous jdbc call possible?

Java Scala Jdbc Asynchronous Nonblocking

What is the Scala identifier "implicitly"?

Scala Implicits

How to turn off INFO logging in Spark?

Python Scala Apache Spark Hadoop Pyspark

What's the (hidden) cost of Scala's lazy val?

Performance Scala Lazy Evaluation

How to read environment variables in Scala

Scala Environment Variables

Scala: write string to file in one statement

Scala Scala 2.9

How to sort by column in descending order in Spark SQL?

Scala Apache Spark Apache Spark-Sql

What's the standard way to work with dates and times in Scala? Should I use Java types or there are native Scala alternatives?

Datetime Scala Jodatime

scala vs java, performance and memory?

Java Performance Scala Memory

Use of def, val, and var in scala

Why does the Scala compiler disallow overloaded methods with default arguments?

Scala Methods Default Overloading

What's the difference between == and .equals in Scala?

Scala Equality Scala Java-Interop

Spark - load CSV file as DataFrame?

Scala Apache Spark Hadoop Apache Spark-Sql Hdfs

Using comparison operators in Scala's pattern matching system

Scala Pattern Matching

How to store custom objects in Dataset?

Scala Apache Spark Apache Spark-Dataset Apache Spark-Encoders

Apache Spark: map vs mapPartitions?

Performance Scala Apache Spark Rdd

How to write to a file in Scala?

Scala File Io Scala 2.8

Difference between Array and List in scala

Arrays List Scala Scala Collections

Understanding what 'type' keyword does in Scala

What makes Scala's operator overloading "good", but C++'s "bad"?

C++Scala Operator Overloading

Difference between object and class in Scala

Scala Class Object

What's the difference between => , ()=>, and Unit=>

What are type lambdas in Scala and what are their benefits?

How to quit scala 2.11.0 REPL?

Scala Scala 2.11

Write single CSV file using spark-csv

Scala Csv Apache Spark Spark Csv

How to convert rdd object to dataframe in spark

Scala Apache Spark Apache Spark-Sql Rdd

Why would I use Scala/Lift over Java/Spring?

Java Spring Scala Lift

Limits of Nat type in Shapeless

Scala Numbers Compiler Optimization Shapeless

How to access test resources in Scala?

What's the best way to inverse sort in scala?

sbt-assembly: deduplication found error

Scala Sbt Sbt Assembly

Hidden features of Scala

Scala Hidden Features

Scala vs. Groovy vs. Clojure

Scala Groovy Clojure Language Comparisons

Are HLists nothing more than a convoluted way of writing tuples?

Scala Types Tuples Hlist Shapeless

Why doesn't the example compile, aka how does (co-, contra-, and in-) variance work?

Generics Scala Covariance Contravariance

How to create SBT project with IntelliJ Idea?

Scala Intellij Idea Lift Sbt

Pros and cons of using sbt vs maven in Scala project

Scala Maven Sbt

IntelliJ Scala Plugin's case class indentation is absurd

Scala Intellij Idea Indentation Case Class

Unable to create Scala class on IntelliJ

Scala Class Intellij Idea

Difference between this and self in self-type annotations?

What does the `#` operator mean in Scala?

Scala Type Systems

Scala constructor overload?

Scala @ operator

Scala Operators

How to define partitioning of DataFrame?

Scala Apache Spark Dataframe Apache Spark-Sql Partitioning

Stream vs Views vs Iterators

Scala Scala Collections

How does '20 seconds' work in Scala?

How to get Scala List from Java List?

Escape a dollar sign in string interpolation

Scala String Interpolation

Scala: Nil vs List()

What is a Manifest in Scala and when do you need it?

How do I view the type of a scala expression in IntelliJ

Scala Intellij Idea

Do scala constructor parameters default to private val?

Scala Scala Primary-Constructor

What is meant by Scala's path-dependent types?

Scala Type Systems Path Dependent-Type

Scala Doubles, and Precision

Scala Double Truncate Rounding

How to split a sequence into two pieces by predicate?

Debugging Scala code with simple-build-tool (sbt) and IntelliJ

Scala Intellij Idea Jetty Sbt

How to pattern match using regular expression in Scala?

What are the best use cases for Akka framework

Java Scala Asynchronous Use Case Akka

Maven package works but Intellij's build fails

Java Scala Maven Intellij Idea

How to print the contents of RDD?

Scala Apache Spark

What are the key differences between Scala and Groovy?

How to optimize for-comprehensions and loops in Scala?

Java Performance Scala For Loop While Loop

How to force IntelliJ IDEA to reload dependencies from build.sbt after they changed?

Scala Intellij Idea Sbt

Split list into multiple lists with fixed number of elements

List Scala Split

What are some compelling use cases for dependent method types?

Scala Haskell Programming Languages Type Systems Dependent Method-Type

How to profile methods in Scala?

Function Scala Profiling Aspect

How to update a mongo record using Rogue with MongoCaseClassField when case class contains a scala Enumeration

Mongodb Class Scala Record Lift

What JSON library to use in Scala?

Why does "split" on an empty string return a non-empty array?

In Scala, what exactly does 'val a: A = _' (underscore) mean?

Scala Initialization

What are all the uses of an underscore in Scala?

How is pattern matching in Scala implemented at the bytecode level?

Performance Scala Pattern Matching Bytecode

How to convert a scala.List to a java.util.List?

Java Scala Scala Java-Interop

Scala downwards or decreasing for loop?

Scala Iterator Loops For Loop

Cleaner way to update nested structures

Scala Case Class Zipper

How to read files from resources folder in Scala?

Scala Scala Collections

SBT stop run without exiting

Scala Sbt Terminate

Why does pattern matching in Scala not work with variables?

Scala Pattern Matching Match

Understanding scala enumerations

What’s the difference between ScalaTest and Scala Specs unit test frameworks?

Unit Testing Scala Comparison Scalatest

Array initializing in Scala

Scala Array Initialization

Scala: List[Future] to Future[List] disregarding failed futures

Abstract attributes in Python

Python Oop Scala Abstract Class

Jvm takes a long time to resolve ip-address for localhost

Java Scala Jvm Localhost Macos Sierra

Preferred way to create a Scala list

How to filter None's out of List[Option]?

What limits does scala place on the "acceptable complexity" of inferred types?

Scala Type Inference

Wrapping null-returning method in Java with Option in Scala?

Java Scala Scala Option

private[this] vs private

What is a "context bound" in Scala?

Scala Scala 2.8 Context Bound

Scala: what is the best way to append an element to an Array?

Arrays Scala Append

What is the rationale behind having companion objects in Scala?

Oop Scala Companion Object

How to parse JSON in Scala using standard Scala classes?

Iterating over Java collections in Scala

Java Scala Collections Scala Java-Interop

Spark - Error "A master URL must be set in your configuration" when submitting an app

Scala Apache Spark

What are the relationships between Any, AnyVal, AnyRef, Object and how do they map when used in Java code?

How to convert an Int to a String of a given length with leading zeros to align?

String Scala Formatting Int

How to do an instanceof check with Scala(Test)

Java Scala Junit Scalatest

Scala how can I count the number of occurrences in a list

Easy idiomatic way to define Ordering for a simple case class

Scala Sorting Case Class

How to load local file in sc.textFile, instead of HDFS

Scala Apache Spark

Idiomatic way to convert an InputStream to a String in Scala

String Scala Inputstream

When to use actors instead of messaging solutions such as WebSphere MQ or Tibco Rendezvous?

Java Scala Jms Actor Akka

Any reason why scala does not explicitly support dependent types?

Scala Path Dependent-Type Dependent Type Shapeless

What are the precise rules for when you can omit parenthesis, dots, braces, = (functions), etc.?

How to get the last date of a particular month with JodaTime?

Java Scala Jodatime

Understanding why Zipper is a Comonad

Scala Functional Programming Zipper Comonad

Private and protected constructor in Scala

comparing sbt and Gradle

Scala Sbt Gradle

How to convert a java.util.List to a Scala list

List Scala Scala Java-Interop

How can I use map and receive an index as well in Scala?

Scala Functional Programming Map

Overload constructor for Scala's Case Classes?

Scala Constructor Overloading Scala 2.8 Case Class

Scala actors: receive vs react

Scala Multithreading Actor

What does param: _* mean in Scala?

Scala Syntax Scala Collections

java.io.IOException: Could not locate executable null\bin\winutils.exe in the Hadoop binaries. spark Eclipse on windows 7

Eclipse Scala Apache Spark

val-mutable versus var-immutable in Scala

Scala Collections Functional Programming Immutability

How to create an empty DataFrame with a specified schema?

Scala Apache Spark Dataframe Apache Spark-Sql

What is the Scala annotation to ensure a tail recursive function is optimized?

Scala Tail Call-Optimization

How can sbt pull dependency artifacts from git?

Git Scala Build Sbt Build Dependencies

Functional design patterns

Scala Haskell Functional Programming Monads

How to compile tests with SBT without running them

Scala Sbt Build Tools

What is the difference between build.sbt and build.scala?

Extract column values of Dataframe as List in Apache Spark

Scala Apache Spark Apache Spark-Sql

Scala framework for a Rest API Server?

Api Rest Scala Lift

How to see dependency tree in sbt?

Scala Dependencies Sbt

What are the disadvantages to declaring Scala case classes?

Scala Case Class

How to sort a list in Scala by two fields?

Scala Sorting Functional Programming

Avoiding memory leaks with Scalaz 7 zipWithIndex/group enumeratees

Scala Scalaz Iterate

I want to get the type of a variable at runtime

Scala Reflection

Scala: What is the difference between Traversable and Iterable traits in Scala collections?

Scala Scala Collections

Where does the "flatmap that s***" idiomatic expression in Scala come from?

What is the correct way to get a subarray in Scala?

Scala Scala Collections

What Automatic Resource Management alternatives exist for Scala?

Scala Resource Management

How to specify JVM maximum heap size "-Xmx" for running an application with "run" action in SBT?

Functional programming - is immutability expensive?

Java Scala Functional Programming

How can I convert immutable.Map to mutable.Map in Scala?

Scala Dictionary Scala 2.8

"new" keyword in Scala

Scala New Operator Keyword

Naming convention for Scala constants?

Scala Naming Conventions Constants

Match multiple cases classes in scala

Scala Pattern Matching

Elegant way to invert a map in Scala

Scala Scala Collections

Scala type programming resources

How do I get the Scala version from within Scala itself?

How to create a list with the same element n-times?

Why are `private val` and `private final val` different?

Scala Private Final

Java compile speed vs Scala compile speed

Java Performance Scala Compilation

scala tuple unpacking

Scala Parameters Tuples

In Scala how do I remove duplicates from a list?

Can someone explain the right way to use SBT?

How does type Dynamic work and how to use it?

When to use val or def in Scala traits?

Scala Inheritance Traits

Renaming column names of a DataFrame in Spark Scala

Scala Apache Spark Dataframe Apache Spark-Sql

How to save DataFrame directly to Hive?

Scala Apache Spark Hive Apache Spark-Sql

Does the JVM prevent tail call optimizations?

Java Jvm Scala Tail Recursion

How do I list all files in a subdirectory in scala?

Scala check if element is present in a list

String List Scala Find

Why is Scala's immutable Set not covariant in its type?

Scala Set Covariance Scala Collections

Usages of Null / Nothing / Unit in Scala

Can I zip more than two lists together in Scala?

Scala Functional Programming List Zip

What does "abstract over" mean?

Scala Abstraction

What are the use cases of scala.concurrent.Promise?

Scala Concurrency

Difference between reduce and foldLeft/fold in functional programming (particularly Scala and Scala APIs)?

Scala Functional Programming Reduce Fold Scalding

How to build an Uber JAR (Fat JAR) using SBT within IntelliJ IDEA?

Scala Intellij Idea Sbt Meta Inf Uberjar

Is there a way to take the first 1000 rows of a Spark Dataframe?

Scala Apache Spark

What is the difference between Scala's case class and class?

Scala Functional Programming Case Class

Building big, immutable objects without using constructors having long parameter lists

Java Oop Scala Immutability

Implicit conversion vs. type class

Scala Coding Style Implicit Conversion

Defining a function with multiple implicit arguments in Scala

Return in Scala

Scala case class inheritance

Scala Inheritance Case Class

How to set heap size for sbt?

What are some example use cases for symbol literals in Scala?

Samples of Scala and Java code where Scala code looks simpler/has fewer lines?

Java Scala Comparison Language Features

Convert List of tuple to map (and deal with duplicate key ?)

How to check whether key or value exist in Map?

Scala Dictionary Collections

Difference between using App trait and main method in scala

Abort early in a fold

Scala Functional Programming

Difference between Abstract Class and Trait

Scala Abstract Class Traits

Package objects

Scala Scala 2.8

Groovy map method of collections

Scala Groovy Functional Programming Map

Ternary Operator Similar To ?:

Map both keys and values of a Scala Map

Editor does not contain a main type

How to read from standard input line by line?

Java Scala Io java.util.scanner

Efficient iteration with index in Scala

Scala Iteration

Differences between these three ways of defining a function in Scala

How do I apply the enrich-my-library pattern to Scala collections?

Scala Collections Enrich My-Library

What is an idiomatic Scala way to "remove" one element from an immutable List?

HowTo: Custom Field in Lift-Record-Squeryl

Scala Lift Record Squeryl

How to show custom failure messages in ScalaTest?

Scala Scalatest Matcher

Scala underscore - ERROR: missing parameter type for expanded function

Scala Scala Placeholder-Syntax

SBT Test-Dependencies in Multiprojects: Make the Test-Code Available to Dependent Projects

Scala Testing Sbt

When are higher kinded types useful?

Scala Haskell Types F#Higher Kinded-Types

Interpreting a benchmark in C, Clojure, Python, Ruby, Scala and others

Python Ruby Scala Clojure Benchmarking

Class broken error with Joda Time using Scala

Scala Sbt Jodatime

Convert a Scala list to a tuple?

List Scala Tuples

Scala multiple type pattern matching

Scala Types Pattern Matching

Reader Monad for Dependency Injection: multiple dependencies, nested calls

Scala Dependency Injection Scalaz

Converting a Java collection into a Scala collection

Java Scala Scala Collections Scala 2.7

How to declare empty list and then add string in scala?

What does => and () => mean in Scala

Is there a good math/stats library for Scala?

Scala Math Statistics

Confused with the for-comprehension to flatMap/Map transformation

Scala Map Monads For Comprehension

Scalaz iteratees: "Lifting" `EnumeratorT` to match `IterateeT` for a "bigger" monad

Scala Monads Scalaz Enumerator Iterate

Scala: Elegant conversion of a string into a boolean

What's the difference between :: and ::: in Scala

scala slick method I can not understand so far

Scala Playframework 2.0 Magic Methods Scalaquery Slick

Get current number of partitions of a DataFrame

Python Scala Dataframe Apache Spark Apache Spark-Sql

When to use the equals sign in a Scala method declaration?

Drop into interpreter during arbitrary scala code location

Debugging Scala Interpreter

How to pattern match multiple values in Scala?

Scala Pattern Matching

Logging while testing through Gradle

Java Scala Logging Gradle

How to wait for several Futures?

Scala Concurrency Future

How to write unit tests in Spark 2.0+?

Scala Unit Testing Apache Spark Junit Apache Spark-Sql

How do I sort an array in Scala?

Remove Characters from the end of a String Scala

What are the differences and similarties between Scala traits vs. Java 8 interfaces?

What are Scala continuations and why use them?

Scala Scala 2.8 Continuations Delimited Continuations

An easy way to get rid of everything generated by SBT?

How to override apply in a case class companion

Scala Pattern Matching Case Class

How to iterate scala map?

Tuple Unpacking in Map Operations

Scala Map Iterator Tuples Iterable Unpacking

Intellij compile failures: "is already defined as"

Scala Intellij Idea Sbt

Is there an equivalent of Scala's Either in Java 8?

Java Scala Java 8

What is the syntax for adding an element to a scala.collection.mutable.Map?

Scala Map Add Mutable Put

What's the difference between multiple parameters lists and multiple parameters per list in Scala?

Scala Currying Partial Application

Markdown to HTML with Java/Scala

Java Scala Markdown

How to pass -D parameter or environment variable to Spark job?

Scala Apache Spark

What is the Scala equivalent of Java's ClassName.class?

What is the motivation for Scala assignment evaluating to Unit rather than the value assigned?

Scala Functional Programming Io Assignment Operator

What do all of Scala's symbolic operators mean?

Scala Operators

Composing Option with List in for-comprehension gives type mismatch depending on order

Scala For Loop Type Mismatch For Comprehension Scala Option

Two ways of currying in Scala; what's the use-case for each?

Scala Coding Style Currying

Scala currying vs partially applied functions

Scala Functional Programming Currying

How to pass Scala array into Scala vararg method?

Arrays Scala Variadic Functions

What is the point of the class Option[T]?

Java Scala Null Functional Programming Monads

How to check whether a String fully matches a Regex in Scala?

What design decisions would favour Scala's Actors instead of JMS?

Java Scala Jms Actor

Where does Scala look for implicits?

Scala Implicit Conversion Implicits

How to read a file as a byte array in Scala

Scala Io Bytearray

Pattern matching vs if-else

How does HashPartitioner work?

Scala Apache Spark Rdd Partitioning

What are the pros of using traits over abstract classes?

On Performance and Java Interoperability: Clojure vs. Scala

Java Performance Scala Clojure Jvm

Scala capture group using regex

Regex String Scala Capturing Group

How to take input from a user in Scala?

Scala classOf for type parameter

How to manage multiple interdependent modules with SBT and IntelliJ IDEA?

Scala Intellij Idea Sbt Sbt Idea

how to set main class in SBT 0.13 project

how to make saveAsTextFile NOT split output into multiple file?

Scala Apache Spark

How do I replace a program written as a sequenced stream of state transitions with scalaz-stream?

Scala Scalaz Scalaz Stream

What is the purpose of type ascriptions in Scala?

Scala Static Typing Ascription

Mixins vs composition in scala

Scala Composition Mixins

How to prevent java.lang.OutOfMemoryError: PermGen space at Scala compilation?

Scala Apache Spark Memory Management Sbt Scalatra Sbt

What is "polymorphism a la carte" and how can I benefit from it?

Scala Functional Programming Typeclass Multimethod

How to configure a fine tuned thread pool for futures?

Multithreading Scala Parallel Processing Threadpool Future

withFilter instead of filter

Scala Lazy Evaluation Scala Collections For Comprehension

How in Scala to find unique items in List

Converting mutable to immutable map

Scala Immutability Mutable Scala Collections

Why does Scala provide both multiple parameters lists and multiple parameters per list?

Scala Currying Partial Application

scala - Any vs underscore in generics

Scala Generics Covariance Any Existential Type

how to filter out a null value from spark dataframe

Scala Apache Spark Apache Spark-Sql Spark Dataframe

How does Scala's apply() method magic work?

Scala Syntactic Sugar Magic Methods Companion Object

Why "avoid method overloading"?

Scala Overloading

What is the difference between self-types and trait subclasses?

Scala Traits Self Type

Load Scala file into interpreter to use functions?

Scala Interpreter

Akka in Scala, exclamation mark and question mark

Scala Operators Akka Actor

Is Scala's actors similar to Go's coroutines?

How to use JDBC source to write and read data in (Py)Spark?

Python Scala Apache Spark Apache Spark-Sql Pyspark

Case class to map in Scala

Scala Case Class

What's the difference of the Akka's Actor with Scala's Actor model

Scala Actor Akka

Doing HTTP request in Scala

Http Scala Scalaz

Get Option value or throw an exception

Pattern Matching `@` Symbol

Scala Pattern Matching

Go to next compiler error across project in IntelliJ

Scala Intellij Idea

How to use Column.isin with list?

Scala Apache Spark Apache Spark-Sql

Explicit Type Conversion in Scala

Scala Type Conversion

How would one do dependency injection in scala?

Scala Dependency Injection

how do I get sbt to use a local maven proxy repository (Nexus)?

Scala Maven Ivy Nexus Sbt

How to transform Scala collection of Option[X] to collection of X

Scala Scala Collections Scala Option

How can I chain implicits in Scala?

Scala Implicit Conversion Implicits

Catching multiple exceptions at once in Scala

Exception Scala Exception Handling Pattern Matching Try Catch

Scalaz state monad examples

Scala Scalaz State Monad

SBT doesn't find file in local maven repository although it's there

Scala Maven Sbt

What is the advantage of using abstract classes instead of traits?

How do I setup multiple type bounds in Scala?

How are the multiple Actors implementation in Scala different?

Scala Actor Akka

Simple and concise HTTP client library for Scala

Scala generic method - No ClassTag available for T

Scala Generics Scala 2.10

Querying Spark SQL DataFrame with complex types

Sql Scala Apache Spark Dataframe Apache Spark-Sql

Is there a scala identity function?

Scala Functional Programming Scala Option

Are FP and OO orthogonal?

Oop Scala Programming Languages Functional Programming Paradigms

How to handle optional query parameters in Play framework

Scala Playframework Playframework 2.0

Functional Programming - Lots of emphasis on recursion, why?

Scala Recursion Functional Programming Tail Recursion

How to use third party libraries with Scala REPL?

Scala Interpreter Read Eval-Print-Loop

Scala's "for comprehension" with futures

Use case of scala.concurrent.blocking

Scala Scala 2.10

Scala - What is the difference between size and length of a Seq?

Scala Scala 2.10 Seq

How should I think about Scala's Product classes?

Scala Functional Programming

List of Scala's "magic" functions

Scala's sealed abstract vs abstract class

Scala Class Abstract Sealed

How do you do dependency injection with the Cake pattern without hardcoding?

How do I compare two arrays in scala?

Arrays Scala Pattern Matching

Why is Scala's syntax for tuples so unusual?

Scala Tuples Iterable Unpacking

What is the forSome keyword in Scala for?

Good example of implicit parameter in Scala?

Scala Parameters Implicit

How do I get around type erasure on Scala? Or, why can't I get the type parameter of my collections?

Scala Type Erasure

Doing something before or after all Scalatest tests

Scala Scalatest

Running tests on Intellij: Class not found

Scala Intellij Idea Gradle

Scala 2.8 collections design tutorial

Scala Scala Collections Scala 2.8

Scala - printing arrays

What's the difference between A<:B and +B in Scala?

Scala list concatenation, ::: vs ++

List Scala Concatenation

Akka Actor not terminating if an exception is thrown

Scala Routing Actor Akka Fault Tolerance

How do I pattern match arrays in Scala?

Scala equivalent of java.util.ArrayList

Java Scala Arraylist

Can someone explain to me what the Shapeless library is for?

Scala Shapeless

What is a TypeTag and how do I use it?

Scala Types Scala 2.10 Reification

Scala double definition (2 methods have the same type erasure)

Scala Compilation Overloading Typeclass Type Erasure

What are practical uses of applicative style?

Scala Haskell F#Functional Programming Applicative

Suitable GUI framework for Scala?

Java Scala User Interface

Documenting Scala 2.10 macros

Scala Macros Documentation Scala 2.10 Scala Macros

How to get an Option from index in Collection in Scala?

Scala Scala Option

When and why should one use Applicative Functors in Scala

Scala Functional Programming Applicative

How to insert double quotes into String with interpolation in scala

How to check if path or file exist in Scala

How does the Cats library in Scala relate to scalaz?

Scala Scalaz Scala Cats

Provide schema while reading csv file as a dataframe

Scala Apache Spark Dataframe Apache Spark-Sql Spark Csv

IntelliJ Cannot Import sbt Project

Scala Intellij Idea Import Sbt

Purpose of Scala's Symbol?

Scala Syntax Language Design Symbols Literals

Scala: “any” and “all” functions

Scala Functional Programming

Scala type keyword: how best to use it across multiple classes

`def` vs `val` vs `lazy val` evaluation in Scala

Scala Properties Lazy Evaluation

Setting up scala with IntelliJ

Java Macos Scala Intellij Idea

What's the difference between Unit and Nothing?

Enforcing Java version for Scala project in sbt?

How do I skip a header from CSV files in Spark?

Scala Csv Apache Spark

Scala: pass Seq to var-args functions

Which programming languages can be used to develop in Android?

Java Android Scala Programming Languages Scripting

Why does IntelliJ IDEA compile Scala so slowly?

Scala Intellij Idea

Extending scala case class without constantly duplicating constructors vals?

Scala Inheritance

What are the problems with an ADT encoding that associates types with data constructors? (Such as Scala.)

Scala Haskell Playframework Functional Programming Argonaut

What does setMaster `local[*]` mean in spark?

Scala Apache Spark

Can't push to the heroku

Git Scala Heroku Intellij Idea

Why is appending to a list bad?

Performance Scala Functional Programming

How can I easily get a Scala case class's name?

Scala Class Classname

Scala: Remove duplicates in list of objects

List Scala Duplicates

Design patterns/best practice for building Actor-based system

Scala Erlang Actor

In Scala, what is an "early initializer"?

What is so wrong with case class inheritance?

Scala Inheritance Case Class

Scala: Boolean to Option

How can I get the name of an Akka actor from within the actor itself?

How to find out which Play version I'm using?

Scala Playframework Typesafe Activator

reduceByKey: How does it work internally?

Scala Apache Spark Rdd

What is a sealed trait?

Scala Sealed Traits

SBT: Start a command line 'run' of the main class of a non-default project

What is the formal difference in Scala between braces and parentheses, and when should they be used?

Scala Syntax Parentheses Braces

Asynchronous IO in Scala with futures

Multithreading Scala Io Future

How to avoid duplicate columns after join?

Scala Apache Spark Apache Spark-Sql

Why does join fail with "java.util.concurrent.TimeoutException: Futures timed out after [300 seconds]"?

Scala Apache Spark Join Apache Spark-Sql

Difference between a Seq and a List in Scala

List Scala Collections Seq

What are type classes in Scala useful for?

Difference between fold and foldLeft or foldRight?

Akka - How many instances of an actor should you create?

How do you remove the _<scala-version> postfix from artifacts built+published with simple-build-tool?

How the get the classOf for a scala object type

What is the idiomatic scala way of finding, if a given string contains a given substring?

Regex String Scala Substring Contains

Decomposing tuples in function arguments

Scala Function Tuples

What's the current state of static analysis tools for Scala?

Scala Static Analysis Sonarqube Scalastyle

Write to multiple outputs by key Spark - one Spark job

Scala Hadoop Output Hdfs Apache Spark

Apache Spark logging within Scala

Scala Logging Apache Spark

What are the differences between final class and sealed class in Scala?

Scala Access Modifiers

Ways to make maven build faster?

Java Multithreading Scala Maven Build

What is monoid homomorphism exactly?

Scala Haskell Functional Programming Category Theory Monoids

What are all the instances of syntactic sugar in Scala?

Scala Syntactic Sugar

Canonical way for empty Array in Scala?

Scala application structure

Need clarification on Scala literal identifiers (backticks)

Scala Futures - built in timeout?

Scala Concurrency

What's recommended .gitignore for Scala/sbt project in IntelliJ IDEA?

Git Scala Intellij Idea Sbt

Spark : how to run spark file from spark shell

Scala Apache Spark Cloudera Cdh Cloudera Manager

What does "coalgebra" mean in the context of programming?

Scala Haskell Functional Programming Category Theory Recursion Schemes

Does Scala support tail recursion optimization?

Performance Scala Tail Recursion

Which programming languages can I use on Android Dalvik?

Java Python Android Scala Dalvik

Traits and abstract methods override in Scala

Does the @inline annotation in Scala really help performance?

Performance Scala Scala 2.8

Scala Hoogle equivalent?

Scala Haskell Type Systems

In Scala, what does "view" do?

Future investment: Erlang vs. Scala

Scala Concurrency Erlang

Restart elasticsearch node

Java Scala Elasticsearch

How to chain multiple different InputStreams into one InputStream

Java Scala Io Inputstream

How to query JSON data column using Spark DataFrames?

Scala Apache Spark Dataframe Apache Spark-Sql Spark Cassandra-Connector

What are the differences and similarities of Scala and Haskell type systems?

Scala Haskell Type Systems

Better String formatting in Scala

String Scala Formatting String Formatting

Read entire file in Scala?

What is the apply function in Scala?

Enforce type difference

What's the Scala way to implement a retry-able call like this one?

Java Scala Functional Programming

Scala Functor and Monad differences

Scala Functional Programming

Can I access my Scala app's name and version (as set in SBT) from code?

Scala Sbt Sbt Buildinfo

What are the differences between Scala middleware choices?

Scala Akka Spray Finagle

Min/max with Option[T] for possibly empty Seq?

Scala Scala Collections

what to choose between require and assert in scala

How to aggregate values into collection after groupBy?

Scala Apache Spark Apache Spark-Sql

Why is "Unable to find encoder for type stored in a Dataset" when creating a dataset of custom case class?

Scala Apache Spark Apache Spark-Dataset Apache Spark-Encoders

How to list all cassandra tables

Scala Apache Spark Cassandra Spark Cassandra-Connector

Akka finite state machine instances

Java Scala Akka State Machine

Building a scala app with maven (that has java source mixed in)

Java Maven 2 Scala

What does a single apostrophe mean in Scala?

Mixing multiple traits in Scala

Scala Mixins Traits

Practical examples of using symbols in Scala?

Scala giving me "illegal start of definition"

Scala equivalent of C#’s extension methods?

Scala Extension Methods

Is there a dbunit-like framework that doesn't suck for java/scala?

Java Database Testing Scala Dbunit

Increment (++) operator in Scala

Scala Increment

How does the “scala.sys.process” from Scala 2.9 work?

Using Scala traits with implemented methods in Java

Java Scala Scala Java-Interop

Nine ways to define a method in Scala?

Scala Methods Function

Install sbt on ubuntu

Scala Debian Ubuntu 12.04 Sbt Deb

How can I cast Integer to String in Scala?

Any Real-World Experience Using Software Transactional Memory?

Scala Haskell Clojure Language Agnostic Stm

Scala: how can I sort an array of tuples by their second element?

Arrays Scala Sorting Tuples

High-performance Concurrent MultiMap Java/Scala

Java Scala Concurrency Multimap

What is the Scala equivalent to a Java builder pattern?

Java Design Patterns Scala

Is there any way to extend an object?

How to check to see if a string is a decimal number in Scala

Do I need to re-use the same Akka ActorSystem or can I just create one every time I need one?

Scala's "postfix ops"

Scala Scala 2.10

How to write database-agnostic Play application and perform first-time database initialization?

Scala Playframework 2.0 Slick

Scala: Why mapValues produces a view and is there any stable alternatives?

What is Scala's yield?

Scala Functional Programming Yield

Difference between forward and tell in akka actors

Scala Akka Actor

Efficiently repeat a character/string n times in Scala

String Scala Char Concatenation String Concatenation

What is the differences between Int and Integer in Scala?

Scala Types Integer Int

Understanding implicit in Scala

Scala Syntax Playframework Keyword

Get index of current element in a foreach method of Traversable?

What does "<:" mean in Scala?

Should implicit classes always extend AnyVal?

Scala Implicit Conversion

Sets, Functors and Eq confusion

Scala Haskell Equality Functor

How is Akka used in Play?

Scala Playframework Akka

Erasure elimination in scala : non-variable type argument is unchecked since it is eliminated by erasure

Scala Type Erasure

Scala Sets contain the same elements, but sameElements() returns false

Scala Scala Collections

How to create a Source that can receive elements later via a method call?

Scala Akka Akka Stream Akka Http

Should I use the final modifier when declaring case classes?

Scala Static Analysis Case Class Scala Wartremover

How do you define a local var/val in the primary constructor in Scala?

Scala Scala Primary-Constructor

What is the meaning of colon, underscore and star in lift's SiteMap(entries:_*)?

Difference between Iterator and Stream in Scala?

Pattern matching with conjunctions (PatternA AND PatternB)

Scala Pattern Matching

In Scala, how can I subclass a Java class with multiple constructors?

Java Scala Constructor Multiple Constructors

Debunking Scala myths

Scala Programming Languages

configure run in eclipse for Scala

How are Scala collections able to return the correct collection type from a map operation?

Scala Collections

How to check for null in a single statement in scala?

Scala Null Inline

Scala pattern matching on sequences other than Lists

Scala Collections Pattern Matching

Triple colon Scala

Unable to find velocity template resources

Java Scala Velocity

Scala on iOS using Avian

Iphone Ios Scala Jvm Avian

How to use java.String.format in Scala?

Java String Scala Format

Difference between case class and case object?

Scala recover or recoverWith

Scala Error Handling Future

What are the biggest differences between Scala 2.8 and Scala 2.7?

Calculating the Moving Average of a List

Scala Functional Programming Clojure

Scala's '::' operator, how does it work?

List Scala Operator Keyword

Replace element in List with scala

What is the difference between a var and val definition in Scala?

How can I get complete stacktraces for exceptions thrown in tests when using sbt and testng?

Scala Testng Sbt Scalatest Slf4j

In Scala, is there an easy way to convert a case class into a tuple?

Scala Tuples Case Class

Finding an item that matches predicate in Scala

Scala Collections Idioms

Impredicative types vs. plain old subtyping

Scala Haskell Functional Programming Subtype Impredicativetypes

Small and good scala projects to learn scala -- especially functional programming and type system

Scala Functional Programming Type Systems

Why can a Scala trait extend a class?

Finding the index of an element in a list scala

Importing spark.implicits._ in scala

Scala Apache Spark

aggregate function Count usage with groupBy in Spark

Java Scala Apache Spark Pyspark Apache Spark-Sql

What are the various join types in Spark?

Scala Apache Spark Apache Spark-Sql Spark Dataframe Apache Spark-2.0

scala Iterable#map vs. Iterable#flatMap

Scala Monads Scala Collections

How can I convert a Java Iterable to a Scala Iterable?

Scala Scala Java-Interop

Scala equivalent to Python generators?

Is there an equivalent to SuppressWarnings in Scala?

Scala Suppress Warnings

Are there any provable real-world languages? (scala?)

Java Scala Testing Functional Programming Formal Verification

What is the difference between a class and a type in Scala (and Java)?

Java Class Scala Types Language Design

Can we use match to check the type of a class

Scala Pattern Matching Match

hashCode in case classes in Scala

Scala Hashcode Case Class

Adding an item to an immutable Seq

How to generate a list of random numbers?

Scala UTC timestamp in seconds since January 1st, 1970

Scala Timestamp Utc

Printing array in Scala

Scala: Merge map

Scala Map Merge

ScalaTest: Assert exceptions in failed futures (non-blocking)

Scala Scalatest

Scala repl throws error

Java Scala Read Eval-Print-Loop