The characters are numbered starting with 0. If i is negative, then the i-th entry counting from the end is provided. If i is out of range, an error is signaled.
i1 : s = "what are you thinking?" o1 = what are you thinking? |
i2 : #s o2 = 22 |
i3 : s_-1, s_19, s_0 o3 = (?, n, w) o3 : Sequence |