is there is indexing in string code example

Example: string index

s = 'Hello'
  len(s)   ## 5
  ## Chars are numbered starting with 0
  s[0]     ## 'H'
  s[1]     ## 'e'
  s[4]     ## 'o'  -- last char is at length-1
  s[5]     ## ERROR, index out of bounds