title: How to retrieve an array with many spritekitnodes?
body: <p>I store an array of spriteNode into an array spacecraftArray with the code as follows.
  Later on, I need to access a specific item in the array. How do I do it?</p>
  <p>There is no unique identifier or index that I can use to direct access a node later selected by my user.</p>
  <pre><code>override func touchesEnded(_ touches: Set&lt;UITouch&gt;, with event: UIEvent?) {
  
      let spacecraft = SKSpriteNode(imageNamed: &quot;spacecraft&quot;)
      spacecraft.createUnit(gameSceneCell: gameSceneCell)
      spacecraftArray.append(spacecraft)
      self.addChild(spacecraft)
  }
  </code></pre>