String::substring

Return the substring of the string between the indexes specified. Indexes are specified in character offsets, not bytes.

"abcdef".substring(1, 3) //-> "bc"
"abc".substring(1, 99) //-> "bc"

Source Codepublic method substring(this: String, from_index: Int, to_index: Int): String {
  __BUILTIN_IMPLEMENTATION
}