Maybe just worth noting this is quite an expensive operation since each grapheme has to be extracted up to the index. If you are processing characters in a string you may find one of these other approaches useful:

1. String.next_grapheme/1 is a good way to help recursing over a string’s graphemes
2. String.graphemes/1 will decompose the string into its graphemes (each a single character string)
3. String,to_charlist/1 will decompose the string into its code points (integer code point values)
4. Binary pattern matching may be good if you know the index you want is in a constant place, for example:

iex(37)> string = "012345"                                              
"012345"
iex(38)> << a :: utf8, b :: utf8, c :: utf8, _rest :: binary >> = string
"012345"
iex(39)> a
48  # <- returns the code point at index 0 of the string

In this case use String.slice/2, for example:

iex> String.slice("elixir", 2..3)
"ix"