title: Replacement for array's indexOf(_:) method in Swift 3
body: <p>In my project (written in Swift 3) I want to retrieve index of an element from array using <code>indexOf(_:)</code> method (existed in Swift 2.2), but I cannot find any replacement for that.</p>
  
  <p>Is there any good replacement for that method in Swift 3 or anything that act similar?</p>
  
  <p><strong>Update</strong></p>
  
  <p>I forget to mention that I want to search in custom object. In code completion I haven't got any hints when typing 'indexof'. But when I try to get index of build in type like <code>Int</code> code completion works and I could use <code>index(of:)</code> method.</p>