type inference still need enhance,any better suggestion for this example?

Posted by iamsungod on Stack Overflow See other posts from Stack Overflow or by iamsungod
Published on 2010-05-24T13:31:33Z Indexed on 2010/05/24 13:41 UTC
Read the original article Hit count: 256

Filed under:

scala

|

clojure

for instance in Clojure:

user=> (map #(* % 2) (concat [1.1 3] [5 7]))

(2.2 6 10 14)

but in Scala:

scala> List(1.1,3) ::: List(5, 7) map (_ * 2)

<console>:6: error: value * is not a member of AnyVal
       List(1.1,3) ::: List(5, 7) map (_ * 2)
                                       ^

Here ::: obtain a list of type List,oops then failed. Can any coding more intuitively like Clojure above?

© Stack Overflow or respective owner

Related posts about scala

ensime scala errors (class scala.Array not found, object scala not found)

as seen on Stack Overflow - Search for 'Stack Overflow'
I've installed ensime according to the README.md file, however, I get errors in the inferior-ensime-server buffer with the following: INFO: Fatal Error: scala.tools.nsc.MissingRequirementError: object scala not found. scala.tools.nsc.MissingRequirementError: object scala not found. at scala… >>> More
infinite loop shutting down ensime

as seen on Stack Overflow - Search for 'Stack Overflow'
When I run M-X ensime-disconnect I get the following forever: string matching regex `\"((?:[^\"\\]|\\.)*)\"' expected but `^@' found and I see this exception when I use C-c C-c Uncaught exception in com.ensime.server.SocketHandler@769aba32 java.net.SocketException: Broken pipe at java… >>> More
How to resolve java.nio.charset.UnmappableCharacterException in Scala 2.8.0?

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm using Scala 2.8.0 and trying to read pipe delimited file like in code snipped below: object Main { def main(args: Array[String]) :Unit = { if (args.length > 0) { val lines = scala.io.Source.fromPath("QUICK!LRU-2009-11-15.psv") for (line <-lines) print(line) } … >>> More
Question on Scala Closure (From "Programming in Scala")

as seen on Stack Overflow - Search for 'Stack Overflow'
I don't understand why authors said that Code Listing 9.1 from "Programming in Scala" use closure. In chapter 9, they show how to refactor code into more less duplicated form, from this original code: object FileMatcher { private def filesHere = (new java.io.File(".")).listFiles def filesEnding(query:… >>> More
Common idiom in Java to Scala, traverse/Iterate Java list into Scala list

as seen on Stack Overflow - Search for 'Stack Overflow'
I am processing a XML document and iterating through nodes. I want to iterate through the nodes and build a new List of some type. How would I do this with Scala: Here is my XML traverse code: def findClassRef(xmlNode: Elem) = { xmlNode\"classDef" foreach { (entry) => val name… >>> More

Related posts about clojure

StackOverflow in compojure web project

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi I've been playing around with clojure and have been using it to build a simple little audio player. The strange thing is that sometimes, maybe one out of twenty, when contact the server I will get the following error: 2010-04-20 15:33:20.963::WARN: Error for /control java.lang.StackOverflowError … >>> More
Wrong number of args passed to: repl$repl

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, I have a trouble with a compojure "Getting started" example that I do not seem to understand. When I run the example from http://weavejester.github.com/compojure/docs/getting-started.html ...I get the following error at the lein repl step: ~/hello-www> lein repl src/hello_www/core.clj Exception… >>> More
Setting the Classpath and Accessing code from book: Programming Clojure

as seen on Stack Overflow - Search for 'Stack Overflow'
(I posted this same question on the Clojure list but haven't got an answer yet. Is anyone here ready to help?) I am going through Programming Clojure and I recently downloaded the code from the books official website. For other utils I can do, for example, (require 'clojure.contrib.str-utils) and… >>> More
How can I define a clojure type that implements the servlet interface?

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm attempting to use deftype (from the bleeding-edge clojure 1.2 branch) to create a java class that implements the java Servlet interface. I would expect the code below to compile (even though it's not very useful). (ns foo [:import [javax.servlet Servlet ServletRequest ServletResponse]]) (deftype… >>> More
Stack overflow in compojure web project

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi I've been playing around with clojure and have been using it to build a simple little audio player. The strange thing is that sometimes, maybe one out of twenty, when contacting the server I will get the following error: 2010-04-20 15:33:20.963::WARN: Error for /control java.lang.StackOverflowError … >>> More