Classic ASP comparison of comma separated lists

Question

Hello,

I have two comma separated lists:-

36,189,47,183,65,50

65,50,189,47

The question is how to compare the two in classic ASP in order to identify and return any values that exist in list 1 but that don't exist in list 2 bearing in mind that associative arrays aren't available.

E.g., in the above example I would need the return value to be 36,183

Thanks

Answer 1

Something like this (untested):

str1 = "36,189,47,183,65,50"
str2 = "65,50,189,47"

arr1 = Split(str1, ",")
arr2 = Split(str2, ",")

for i = 0 to UBound(arr1)  
   found = false
   for j = 0 to UBound(arr2)
      if arr1(i) = arr2(j) then
         found = true
      end if
   next   
   if found = false then
      Response.Write(arr1(i))
   end if
next

Answer 2

In order to solve this with regular expression you can use lookaheads (both positive and negative) and references, for example:

(zyx:~) % echo '36,189,47,183,65,50;65,50,189,47' | grep -oP '((?>(?<![^,;])[^,;]+))(?=.*;)(?!.*;(|.*,)\1(?=,|$))'
36
183

Other variant (works in PCRE but not in perl):

(zyx:~) % echo '36,189,47,183,65,50' | grep -oP '((?!(?<=,|^)65|50|189|47(?=,|$))(?<=,|^)[^,]+(?=,|$))'
36
183

Have no idea whether any of these works in asp.