title: Why strings cannot be indexed by integer values
body: <p>I learned that Swift strings cannot be indexed by integer values. I remembered it and I use the rule. But I've never fully understood the mechanic behind it.</p>
  
  <p>The explanation of from the official document is as follows </p>
  
  <p>"<em>Different characters can require different amounts of memory to store, so in order to determine which Character is at a particular position, you must iterate over each Unicode scalar from the start or end of that String. For this reason, Swift strings cannot be indexed by integer values</em>"</p>
  
  <p>I've read it several times, I still don't quite get the point. Can someone explain me a bit more why Swift String cannot be indexed by integer values?</p>
  
  <p>Many Thanks</p>