title: Get values of an Array from an Observable
body: <p>I have an <code>Observable&lt;MoviesResponse&gt;</code>. My <code>MovieResponse</code> class contains a <code>getResults()</code> methods returning a <code>List&lt;Result&gt;</code>. This Result class has a <code>getTitle()</code> methods returning a String. I want to call the <code>getTitle()</code> methods of all my <code>Result</code> objects to get all the titles of my movies.</p>
  
  <p>I achieved this with the code below using a foreach loop but I think there is a better way to do this by chaining RxJava operators, I just can't figure it out...</p>
  
  <p>Subscription :</p>
  
  <pre><code>Observable&lt;MoviesResponse&gt; moviesResponseObservable = apiService.getTopRatedMoviesObservable(API_KEY);
  
  subscription = moviesResponseObservable
                  .subscribeOn(Schedulers.io())
                  .observeOn(AndroidSchedulers.mainThread())
                  .subscribe(new Observer&lt;MoviesResponse&gt;() {
                      @Override
                      public void onCompleted() {
  
                      }
  
                      @Override
                      public void onError(Throwable e) {
  
                      }
  
                      @Override
                      public void onNext(MoviesResponse moviesResponse) {
                          List&lt;Result&gt; results = moviesResponse.getResults();
                          for (Result r:results) {
                              Log.d(LOG_TAG,r.getTitle());
                          }
                      }
                  });
  </code></pre>
  
  <p>Interface :</p>
  
  <pre><code>public interface ApiService {           
      @GET("movie/top_rated")
      Observable&lt;MoviesResponse&gt; getTopRatedMoviesObservable(@Query("api_key") String apiKey);
  }
  </code></pre>