procedure - How to call a list for update multiple times until a condition is fulfilled in Netlogo -

i new netlogo , still learning , want call list after update done , update until condition reached , if have list

let xy [[-2 6][-1 6][0 6][-1 6][-2 6][1 5][2 5][-3 9][-4 9][-5 9][-6 9][-3 9]]  let same true 

i trying remove list first sublist between 2 same elements [-2 6 ][-1 6][0 6][-1 6][-2 6] want remove sublist between other 2 same elements [-3 9][-4 9][-5 9][-6 9][-3 9] until there no more elements repeat in case result should [[1 5] [2 5]] , control list after removing sublists condition:

if length xy = length remove-duplicates xy [ set same false ] 

i have done removal code below , removes first sublist might have lot of sublists , , want know how after 1 removal can again updated list (in these case should somehow take final-list in code) , control again these condition. thinking to-report procedure , while loop , example (maybe wrong this)

 to-report update-list [list]   while [same != false ]    [ ; removal stuff     set list-xy item position (first modes xy) xy xy    let first-pos position (first modes xy)  xy     set list-temp remove-item first-pos xy     set sec-pos position list-xy list-temp + 1    set sublist-1 sublist xy 0 first-pos     set sublist-2 sublist xy sec-pos length xy    set final-list sentence sublist-1 sublist-2    set xy final-list    ; condition if don't have duplicates size of 2 lists should have same size , no duplicates  if length xy = length remove-duplicates xy      [ set same false ]     ]     report update-list xy  

i not sure report @ end of procedure , how recall list again, can remove sublists.

any ideas appreciated, thank

this easiest solve using recursion:

to-report remove-fenced-sublists [xs]   if empty? xs     [ report [] ]   let pos position first xs butfirst xs   if not is-number? pos     [ report fput first xs remove-fenced-sublists butfirst xs ]   report remove-fenced-sublists sublist xs (pos + 2) length xs end 

sample run:

observer> show remove-fenced-sublists [[-2 6][-1 6][0 6][-1 6][-2 6][1 5][2 5][-3 9][-4 9][-5 9][-6 9][-3 9]] observer: [[1 5] [2 5]]