Command Reference : String and Date Function Reference
Syntax: @rinstr(str1, str2[, n])
Argument 1: string, str1
Argument 2: string, str2
Argument 3: integer, n
Return: integer
Starting at the end of base string str1 and searching in reverse, this function finds the starting position of the target string str2. By default, the function returns the location of the first occurrence of str2 in str1 (in reverse). You may provide an optional integer n to change the occurrence. If the occurrence of the target string is not found, @RINSTR will return a 0.
@rinstr("1.2341534", "34", 2)
return the value 4, since the substring “34” appears a second time (from the end of the string) beginning in the fourth character of the base string.
See also @instr and @mid.