String substr(String x, Int i, Int len)
x: The original string
i: The starting index
len: The substring length
Starting at character i, return the len characters long substring. Throws an Exception if len is negative, or if i is out-of-bounds. In Kaya 0.2.4 and earlier, an Exception was also thrown if len was zero. The empty string is now returned in this case.
If the starting index is negative, then it will be counted in characters from the end of the string.
x = "abcdef"; s = substr(x,0,2); // "ab" s = substr(x,4,1); // "e" s = substr(x,3,10); // "def" (len truncated) s = substr(x,-4,2); // "cd"