title: Index Section Titles in UITableView Using A-Z in sectionForSectionIndexTitle Method
body: <p>I have hundreds of sections in my UITableView. I've put all my sections in an array, and I've changed that array to only contain capital letters and removed any repeating characters.</p>
  
  <pre><code>//sample array
  let sectionsArray: [String] = [Apple, Asparagus, Banana, Barley, Cucumber...]
  
  var firstLettersOfSections: [String] = []
  
  firstLettersOfSections = sectionsArray.map { String($0.characters.first!).uppercased() }
          firstLettersOfSections = removeDuplicates(&amp;firstLettersOfSections)
  </code></pre>
  
  <p>I returned <code>firstLettersOfSections</code> in the <code>sectionIndexTitles</code> method:</p>
  
  <pre><code>override func sectionIndexTitles(for tableView: UITableView) -&gt; [String]? {
      return firstLettersOfSections
  }
  </code></pre>
  
  <p>This code produces the proper alphanumeric characters at the right side of the tableView, however, when the characters are tapped on, they go to the section index that corresponds to the index of <code>firstLettersOfSections</code>.</p>
  
  <p>What do I put in the <code>sectionForSectionIndexTitle</code> tableView method so that when I tap on an alphanumeric character in the vertical list, it goes to the first section with the specified letter or number and such that the indexing is case insensitive?</p>