Maxima Function
substring (string, start)
substring(string,start,end)
Returns the substring of string beginning at position start and ending at position end. The character at position end is not included. If end is not given, the substring contains the rest of the string. Note that the first character in string is in position 1.
(%i1) substring("substring",4); (%o1) string (%i2) substring(%,4,6); (%o2) in