1 Rbisect <- function(lst, value){
 2     low=1
 3     high=length(lst)
 4     mid=length(lst)%/%2
 5     if (lst[low]==value) low
 6     else if (lst[high]==value) high
 7     else{
 8     while (lst[mid] != value) {
 9       if (value > lst[mid]){
10         low = mid+1
11       } else if (value < lst[mid]) {
12         high = mid - 1
13       } 
14       if(high<low){
15          mid=-1;break
16       }
17       mid=(low+high)%/%2
18     }
19       mid
20 }
21 }