Java's "forEach" to Scala

Question

How can the following be converted to scala? If I live it as it is, I'm getting a big type mismatch expected

.entrySet().forEach(entry -> {..})

I tried specifying entry to java.util.Map.Entry, or changing to scala foreach, doesn't work.

Let me know if you need any more info/code, and I'll create some dummy example since I'm not allowed to post the exact code.

I'd say you want an implicit conversion. http://stackoverflow.com/questions/7481204/smooth-way-of-using-functiona-r-java-interface-from-scala — Marko Topolnik, Feb 23 '15 at 09:17
If it's a `java.util.Map` then you either want the implicit conversion for the function as suggested by @MarkoTopolnik, or to convert it to a scala map using `.asScala` with `import scala.util.JavaConverters._` at the top. Or you can explicitly instantiate a `new Function(){}` the way you would in Java. If it's a `scala.collection.Map` then the `for(entry ← ...)` approach is what you want. — lmm, Feb 23 '15 at 09:29

score 3 · Accepted Answer · edited May 23 '17 at 11:50

3

check this

for each in scala

for(entry<-entrySet){
//
}

or

entrySet.foreach{entry=>
//
}

or

.entrySet.map{entry => 
//
}

edited May 23 '17 at 11:50

Community

answered Feb 23 '15 at 09:23

Govind Singh

You should use `foreach`, not `map`. `map` may be lazy depending on the data type of `entrySet`. – Feb 23 '15 at 09:24
`for (entry<-entrySet)` is more a equivalent of `for (entry : entrySet())` in Java. – user11153 Feb 23 '15 at 09:25
@K-RAD yeah it works on scala collections you have to convert it to scala collections – Govind Singh Feb 23 '15 at 09:33
foreach worked nicely with import scala.collection.JavaConversions._ – KKO Feb 23 '15 at 09:55

score 1 · Answer 2 · answered Feb 23 '15 at 09:32

1

Just

import scala.collection.JavaConversions._

for an implicit conversion to scala collections.

answered Feb 23 '15 at 09:32

gun

3

Please don't suggest using implicit conversions. [Decorators](http://www.scala-lang.org/api/current/index.html#scala.collection.convert.DecorateAsScala) are the way to go: `import scala.collection.convert.decorateAsScala._; javaCollection.asScala.foreach(x => doSomething(x))`. – Vladimir Matveev Feb 23 '15 at 19:27
2

Good point! It's explained in this post: http://stackoverflow.com/questions/8301947/what-is-the-difference-between-javaconverters-and-javaconversions-in-scala – gun Feb 24 '15 at 08:39
Both `scala.collection.JavaConversions._` and `scala.collection.convert.decorateAsScala` are deprecated. The current way is (until it is also deprecated in some future) `import scala.collection.JavaConverters._; javaCollection.asScala.foreach(x => doSomething(x))` – yerlilbilgin Nov 27 '18 at 13:04

2 Answers2