title: access index of struct item field in Golang
body: <p>Is there any possibility to change character with some index in struct field if it is string?</p>
  
  <p>I mean I can do such manipulations with string type:</p>
  
  <pre><code>func main() {
      v := "Helv"
      v[3] = "p"
  }
  </code></pre>
  
  <p>How can I do same thing with struct fields? Below assignment doesn't work.</p>
  
  <pre><code>type ik struct {
      a int
      b string
  }
  
  func main() {
      f := ik{1, "Pasis"}
      fmt.Println(f.b)
      f.b[2] = "r"
  }
  </code></pre>