[R] Conditionally remove rows with logic

[Jim Lemon]

Hi Jennifer,
A very pedestrian method, but I think it does what you want.

remove_rows_after_1<-function(x) {
 nrows<-dim(x)[1]
 rtr<-NA
 rtrcount<-1
 got1<-FALSE
 thisID<-x$ID[1]
 for(i in 1:nrows) {
  if(x$ID[i] == thisID && got1) {
   rtr[rtrcount]<-i
   rtrcount<-rtrcount+1
  }
  if(x$ID[i] != thisID) {
   thisID<-x$ID[i]
   got1<-FALSE
  }
  if(x$ID[i] == thisID && x$LABEL[i]) got1<-TRUE
 }
 return(rtr)
}

The function returns the indices of rows to be removed.

Jim


On Mon, Aug 8, 2016 at 8:21 AM, Jennifer Sheng
<jennifer.sheng2002 at gmail.com> wrote:
> Dear all,
>
> I need to remove any rows AFTER the label becomes 1.  For example, for ID
> 1, the two rows with TIME of 15 & 18 should be removed; for ID 2, any rows
> after time 6, i.e., rows of time 9-18, should be removed.  Any
> suggestions?  Thank you very much!
>
> The current dataset looks like the following:
> ID     TIME     LABEL
> 1        0            0
> 1        3            0
> 1        6            0
> 1        9            0
> 1        12          1
> 1        15          0
> 1        18           0
> 2        0            0
> 2        3            0
> 2        6            1
> 2        9            0
> 2        12          0
> 2        15          0
> 2        18          0
>
> Thanks a lot!
> Jennifer
>
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