title: How to return boolean value when subscribe with rxjava
body: <p>I have an arrayList. And I need to return true if at least one item from my array isNumber. 
  Here is my code:</p>
  
  <pre><code>    private boolean hasNumber(ArrayList&lt;Item&gt; items) {
            return Observable.fromIterable(items)
                 .filter(Item::isNumber)                
                  .toList()
                  .subscribeOn(Schedulers.io())
                  .observeOn(AndroidSchedulers.mainThread())
                  .map(items-&gt; items.size() &gt; 0)
                  .subscribe(result -&gt; "");
     }
  </code></pre>
  
  <p>But I can't return true/false from this method. I don't understand how to return value with rxJava. Please help me.</p>