Look up TokenAt() I use that all the time.
TokenAt("1,2,3,4",2,",") = 3
the selected comma separated item in the list is 3.
Edit: Actually here is the manual entries:
tokenat(src, index, separator)
Return the Nth token from src, splitting the string by separator. For example, tokenat("apples|oranges|bananas", 1, "|") returns oranges.
tokencount(src, separator)
Count how many tokens occur in src using separator. For example, tokencount("apples|oranges|bananas", "|") returns 3.