Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Login
Remember
Register
Ask
Q&A
All Activity
Hot!
Unanswered
Tags
Users
Ask a Question
Ask a Question
Categories
All categories
Topic[话题] (13)
Life[生活] (4)
Technique[技术] (2.1m)
Idea[创意] (3)
Jobs[工作] (2)
Others[杂七杂八] (18)
Code Example[编程示例] (0)
Recent questions tagged scala
0
votes
482
views
1
answer
scala - Advantages of F-bounded polymorphism over typeclass for return-current-type problem
Returning the current type questions are often asked on StackOverflow. Here is one such example. The usual answers seem ... : Bar = Bar(Scala) See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
455
views
1
answer
scala - Akka-Stream implementation slower than single threaded implementation
UPDATE FROM 2015-10-30 based on Roland Kuhn Awnser: Akka Streams is using asynchronous message ... .apache.avro.specific.SpecificRecordBuilderBase<Event> implements org.apache...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
595
views
1
answer
scala - How is this case class match pattern working?
I've just seen this case class in the Scala actors package: case class ! [a](ch: Channel[a], msg: a) And ... way to methods ending in a colon : See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
791
views
1
answer
scala - Missing parameter type error by calling toSet?
Trying to generate, from a list of chars, a list of unique chars mapped to their frequency - e.g. ... why Scala complains about this syntax? See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
1.0k
views
1
answer
scala - Spark 2.2 Illegal pattern component: XXX java.lang.IllegalArgumentException: Illegal pattern component: XXX
I'm trying to upgrade from Spark 2.1 to 2.2. When I try to read or write a dataframe to a location (CSV or ... |-- age: long (nullable = false) See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
940
views
1
answer
scala - Spark: long delay between jobs
So we are running spark job that extract data and do some expansive data conversion and writes to several ... enable.summary-metadata to false See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
947
views
1
answer
scala - Getting subclasses of a sealed trait
Is it possible (via macros, some form of Shapeless automagic or otherwise) to obtain a list of the subclasses ... At compile time? At runtime? See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
557
views
1
answer
scala - How to restrict actor messages to specific types?
In Akka, is there a way to restrict messages to actors to be of a specific static type other than using the " ... level messages (Exit, etc.). See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
748
views
1
answer
scala - Limits of Nat type in Shapeless
In shapeless, the Nat type represents a way to encode natural numbers at a type level. This is used for example ... Scala compiler to give up? See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
620
views
1
answer
scala - "dynamically" creating case classes with macros
I would like to create a macro generated hierarchy of sealed abstract and case classes. There was an example ... to resolve all the classes. See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
615
views
1
answer
scala - Why isn't Validation a Monad?
an example use case: def div2(i: Int): Validation[String, Int] = if (i%2 == 0) Validation.success(i/2) else ... I'm using scalaz 7.0.0-M2 See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
894
views
1
answer
scala - assembly-merge-strategy issues using sbt-assembly
I am trying to convert a scala project into a deployable fat jar using sbt-assembly. When I run my assembly ... be doing wrong here? Thanks See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
686
views
1
answer
scala - Converting Map[String,Any] to a case class using Shapeless
The question here asks about mapping a case class to a Map[String,Any]. I was wondering what would be the ... should I do that with Shapeless. See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
697
views
1
answer
scala - Map versus FlatMap on String
Listening to the Collections lecture from Functional Programming Principles in Scala, I saw this example: scala> val s ... map on the String? See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
575
views
1
answer
scala - Validation versus disjunction
Suppose I want to write a method with the following signature: def parse(input: List[(String, String)]): ... prefer one over the other? See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
726
views
1
answer
scala - How do I run an sbt main class from the shell as normal command-line program?
How can I run an sbt app from the shell, so that I can run my app as a normal command-line program (as if ... like there must be a better way. See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
635
views
1
answer
scala - How do I get an instance of the type class associated with a context bound?
Note: I'm posing this question to answer it myself, but other answers are welcome. Consider the following simple ... can invoke the plus method? See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
647
views
1
answer
scala - Spark RDD default number of partitions
Version: Spark 1.6.2, Scala 2.10 I am executing below commands In the spark-shell. I am trying to see ... giving the result as 4 partitions ? See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
711
views
1
answer
scala - How to reference external sbt project from another sbt project?
I have the following setup of a Scala application and a common core library: root -> /ApplicationA -> / ... of having this project dependency? See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
599
views
1
answer
scala - Should I use the final modifier when declaring case classes?
According to scala-wartremover static analysis tool I have to put "final" in front of every case classes I create: ... Who is right, and why? See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
654
views
1
answer
scala - How to split a sequence into two pieces by predicate?
How do I split a sequence into two lists by a predicate? Alternative: I can use filter and filterNot, or write ... general (built-in) method ? See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
944
views
1
answer
scala - How to force IntelliJ IDEA to reload dependencies from build.sbt after they changed?
I'm using IntelliJ IDEA 13 (Community Edition) with the Scala plugin. My initial import of an existing ... the dependencies from build.sbt? See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
705
views
1
answer
scala - Split list into multiple lists with fixed number of elements
How to split a List of elements into lists with at most N items? ex: Given a list with 7 elements, create groups of ... ,4), List(5,6,"seven")) See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
487
views
1
answer
scala - Why spark-shell fails with NullPointerException?
I try to execute spark-shell on Windows 10, but I keep getting this error every time I run it. I ... value sqlContext import sqlContext.sql ^ See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
572
views
1
answer
scala - Instantiating a case class from a list of parameters
Given: case class Foo(a: Int, b: String, c: Double) you can say: val params = Foo(1, "bar", ... .productIterator.toList) res11: Boolean = true See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
513
views
1
answer
scala - Package objects
What are package objects, not so much the concept but their usage? I've tried to get an example working and the ... common use? If so, how? See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
631
views
1
answer
scala - How to wait for several Futures?
Suppose I have several futures and need to wait until either any of them fails or all of them succeed. For ... . How would you implement it? See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
0
votes
622
views
1
answer
scala - How to print the contents of RDD?
I'm attempting to print the contents of a collection to the Spark console. I have a type: linesWithSessionId: org. ... I can view its contents? See Question&Answers more detail:os...
asked
Oct 17, 2021
in
Technique[技术]
by
深蓝
(
71.8m
points)
scala
Page:
« prev
1
...
18
19
20
21
22
23
24
25
26
27
28
...
42
next »
Ask a question:
Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question
Just Browsing Browsing
[1] IIS虚拟主机,如何设置Basic认证
[2] 多模块的SpringBoot项目如何启动?
[3] How to obtain previous page's URL in php
[4] hdl - chip Mux4way16 not run ontil the end on ?HardwareSimulator (VHDL)
[5] elementui tree拖拽的扩展
[6] element-ui表格hover效果错误怎么办?
[7] c - Memory leak with valgrind, where can I free my pointer
[8] b站视频如何内嵌进自己的页面
[9] element上传问题
[10] integer - Is it a matter of precision or just wrongly typed syntax?
2.1m
questions
2.1m
answers
60
comments
56.8k
users
Most popular tags
javascript
python
c#
java
How
android
c++
php
ios
html
sql
r
c
node.js
.net
iphone
asp.net
css
reactjs
jquery
ruby
What
Android
objective
mysql
linux
Is
git
Python
windows
Why
regex
angular
swift
amazon
excel
algorithm
macos
Java
visual
how
bash
Can
multithreading
PHP
Using
scala
angularjs
typescript
apache
spring
performance
postgresql
database
flutter
json
rust
arrays
C#
dart
vba
django
wpf
xml
vue.js
In
go
Get
google
jQuery
xcode
jsf
http
Google
mongodb
string
shell
oop
powershell
SQL
C++
security
assembly
docker
Javascript
Android:
Does
haskell
Convert
azure
debugging
delphi
vb.net
Spring
datetime
pandas
oracle
math
Django
联盟问答网站-Union QA website
Xstack问答社区
生活宝问答社区
OverStack问答社区
Ostack问答社区
在这了问答社区
在哪了问答社区
Xstack问答社区
无极谷问答社区
TouSu问答社区
SQlite问答社区
Qi-U问答社区
MLink问答社区
Jonic问答社区
Jike问答社区
16892问答社区
Vigges问答社区
55276问答社区
OGeek问答社区
深圳家问答社区
深圳家问答社区
深圳家问答社区
Vigges问答社区
Vigges问答社区
在这了问答社区
DevDocs API Documentations
Xstack问答社区
生活宝问答社区
OverStack问答社区
Ostack问答社区
在这了问答社区
在哪了问答社区
Xstack问答社区
无极谷问答社区
TouSu问答社区
SQlite问答社区
Qi-U问答社区
MLink问答社区
Jonic问答社区
Jike问答社区
16892问答社区
Vigges问答社区
55276问答社区
OGeek问答社区
深圳家问答社区
深圳家问答社区
深圳家问答社区
Vigges问答社区
Vigges问答社区
在这了问答社区
在这了问答社区
DevDocs API Documentations
Xstack问答社区
生活宝问答社区
OverStack问答社区
Ostack问答社区
在这了问答社区
在哪了问答社区
Xstack问答社区
无极谷问答社区
TouSu问答社区
SQlite问答社区
Qi-U问答社区
MLink问答社区
Jonic问答社区
Jike问答社区
16892问答社区
Vigges问答社区
55276问答社区
OGeek问答社区
深圳家问答社区
深圳家问答社区
深圳家问答社区
Vigges问答社区
Vigges问答社区
在这了问答社区
DevDocs API Documentations
广告位招租
...