The  `_` has to be put at the end - not at the beginning:

*Exclude Map and Set from the import*

    import scala.collection.mutable.{Map =&gt; _, Set =&gt; _, _}

*Exclude Set and rename Map to ScalaMutableMap*

    import scala.collection.mutable.{Map=&gt;ScalaMutableMap, Set =&gt; _, _}

See the detailed info in [Scala Refererence][1], page 50, paragraph 4.7

  [1]: http://www.scala-lang.org/docu/files/ScalaReference.pdf#page=58

My problem is that when I start application and user didn&#39;t open my `PreferenceActivity` so when I retrieve them don&#39;t get any default values defined in my preference.xml file.

preference.xml file:

    &lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
    &lt;PreferenceScreen xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
        android:key=&quot;applicationPreference&quot; android:title=&quot;@string/config&quot;
        &gt;
        &lt;ListPreference
                android:key=&quot;pref1&quot;
                android:defaultValue=&quot;default&quot;
                android:title=&quot;Title&quot;
                android:summary=&quot;Summary&quot;
                android:entries=&quot;@array/entry_names&quot;
                android:entryValues=&quot;@array/entry_values&quot;
                android:dialogTitle=&quot;@string/dialog_title&quot;
        /&gt;                  
    &lt;/PreferenceScreen&gt;

Snippet from my main Activity (`onCreate` method):

        SharedPreferences appPreferences = PreferenceManager.getDefaultSharedPreferences(this);        
        String pref1 = appPreferences.getString(&quot;pref1&quot;, null);

In result I end up with a `null` value.

Initialize preferences from XML in the main Activity

How long are files usually kept in a browser&#39;s cache? I&#39;m wondering about the general population - how long would I need to wait to be reasonable certain that most people&#39;s caches will refetch the file? 

How long are files usually kept in a browser&#39;s cache

[Language FAQ][1] says 

    import scala.collection.mutable.{_, Map =&gt; _, Set =&gt; _}

should import all classes from package `scala.collection.mutable`, except `Map` and `Set`. But it gives me this error: 

    error: &#39;}&#39; expected but &#39;,&#39; found.
           import scala.collection.mutable.{_, Map =&gt; _, Set =&gt; _}

Is there still a way to do this?

  [1]: http://scala.sygneca.com/faqs/language#how-do-i-import


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

<a href="http://scala.sygneca.com/faqs/language#how-do-i-import" target="_blank" rel="noopener noreferrer">Language FAQ</a> says
<pre><code class="hljs language-javascript">import scala.collection.mutable.{_, Map => _, Set => _}
</code></pre>
should import all classes from package <code>scala.collection.mutable</code>, except <code>Map</code> and <code>Set</code>. But it gives me this error:
<pre><code class="hljs language-javascript">error: '}' expected but ',' found.
 import scala.collection.mutable.{_, Map => _, Set => _}
</code></pre>
Is there still a way to do this?

[Hoogle][1] allows you to search many standard Haskell libraries by either function name, or by approximate type signature. I find it very useful. Is there anything like Hoogle for Scala? Search in [ScalaDoc 2][2] only finds types and packages by name.


  [1]: http://www.haskell.org/hoogle/
  [2]: http://www.scala-lang.org/archives/rc-api/index.html

Scala Hoogle equivalent?

I&#39;m trying to find the &#39;right&#39; actor implementation. I realized there is a bunch of them and it&#39;s a bit confusing to pick one. Personally I&#39;m especially interested in remote actors, but I guess a complete overview would be helpful to many others. This is a pretty general question, so feel free to answer just for the implementation you know about.

I know about the following Scala Actor implementations (SAI). Please add the missing ones.

- Scala 2.7 (difference to)
- Scala 2.8
- Akka (http://www.akkasource.org/)
- Lift (http://liftweb.net/)
- Scalaz (http://code.google.com/p/scalaz/)
--- --- --- --- --- --- --- --- --- --- --- --- 
- What are the target use-cases for these SAIs (lightweight vs. &quot;heavy&quot; enterprise framework)?
- do they support remote actors? What shortcomings do remote actors have in the SAIs?
- How is their performace?
- How active is there community?
- How easy are they to get started? How good is the documentation?
- How easy are they to extend? 
- How stable are they? Which projects are using them?
- What are their shortcomings?
- What are their design principles?
  - Are they thread based or event based (receive/ react) or both?
  - Nested receiveS
  - hotswapping the Actor’s message loop

Different Scala Actor Implementations Overview

I like Scala&#39;s propose of operator precedence but in some rare cases, unmodified rules may be inconvenient, because you have restrictions in naming your methods. Are there ways to define another rules for a class/file, etc. in Scala? If not, would it be resolved in the future?


Operator precedence in Scala

I need some code samples (and I also really curious about them) of Scala and Java code which show that Scala code is more simple and concise then code written in Java (of course both samples should solve the same problem).

If there is only Scala sample with comment like &quot;this is abstract factory in Scala, in Java it will look much more cumbersome&quot; then this is also acceptable.

Thanks!

I like most of all accepted and [this][1] answers


  [1]: https://stackoverflow.com/questions/2952732/samples-of-scala-and-java-code-where-scala-code-looks-simpler-has-fewer-lines/2961620#2961620

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

One of the new features of Scala 2.8 are context bounds. What is a context bound and where is it useful?

Of course I searched first (and found for example [this][1]) but I couldn&#39;t find any really clear and detailed information.


  [1]: https://stackoverflow.com/questions/2961986/how-do-you-write-an-idiomatic-scala-quicksort-function/2962799#2962799

What is a &quot;context bound&quot; in Scala?

What are package objects, not so much the concept but their usage?

I&#39;ve tried to get an example working and the only form I got to work was as follows:

    package object investigations {
        val PackageObjectVal = &quot;A package object val&quot;
    }

    package investigations {

        object PackageObjectTest {
            def main(args: Array[String]) {
                println(&quot;Referencing a package object val: &quot; + PackageObjectVal)
            }
        }
    }

Observations I&#39;ve made so far are:

    package object _root_ { ... }

is disallowed (which is reasonable),

    package object x.y { ... }

is also disallowed.

It seems that a package object must be declared in the immediate parent package and, if written as above, the brace delimited package declaration form is required.

Are they in common use? If so, how?


Package objects

I can see in the API docs for [Predef][1] that they&#39;re subclasses of a generic function type (From) =&gt; To, but that&#39;s all it says.  Um, what?  Maybe there&#39;s documentation somewhere, but search engines don&#39;t handle &quot;names&quot; like &quot;&lt;:&lt;&quot; very well, so I haven&#39;t been able to find it.

Follow-up question: when should I use these funky symbols/classes, and why?


  [1]: https://scala-lang.org/files/archive/api/2.8.2/scala/Predef$.html

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

For reading, there is the useful abstraction `Source`. How can I write lines to a text file?


How to write to a file in Scala?

How can I convert `immutable.Map` to `mutable.Map` in Scala so I can update the values in `Map`?



Content Type	Original Author	Original Content on Stackoverflow
Question	Alexey Romanov	View Question on Stackoverflow
Solution 1 - Scala	Patrick	View Answer on Stackoverflow

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

Scala Problem Overview

Scala Solutions

Solution 1 - Scala

How long are files usually kept in a browser's cache

Initialize preferences from XML in the main Activity

Attributions