How to remove duplicates using equality matrix in R?

Question

I have 3 polygons, which are: 1st is unique, 2 & 3 are equal. (I use SpatialPolygons matrix but's not important). I just need to know how to implement a function to delete those duplicated polygons using following matrix:

d = rgeos::gEquals(sps, byid = T, returnDense = T)

      1     2     3
1 FALSE FALSE FALSE
2 FALSE  TRUE  TRUE
3 FALSE  TRUE  TRUE

So I need to leave 1 and remove 2 or 3. I have only this short data but if I have longer and will do mistake here it would not work further although it may work for short example. Anyway, this doesn't work at all, because I don't know how to make it stick.

I try something like this:

saved = NULL
      for (i in 1:nrow(d)) {  #i=1
        e = which(d[i,] == T)
        if (any(e == T)) {
          # saved
          saved = c(saved, i)
          d[i,] = F; d[,i] = F
        }
      }

where in saved I just need indices to leave (1,2) or (1,3) then I know what to do next.

EDIT

In fact, this post How can I remove all duplicates so that NONE are left in a data frame? is helpful, because applying

nd = !duplicated(d)
saved = as.numeric(rownames(d)[which(nd)])

I get the required result, but not sure it's correct when I have larger matrix.

Related, possible duplicate of https://stackoverflow.com/q/13763216/680068 — zx8754, Jul 16 '19 at 15:24
I can't use method from this post because I have an matrix only as a return of `gEquals` function. The output should be just indices of elements to save (here: 1,2 or 1,3) in a vector. — Peter.k, Jul 16 '19 at 15:29
Could you clarify the output more, why 1,2 or 1,3? Why not 2 or 3? — zx8754, Jul 16 '19 at 15:36

How to remove duplicates using equality matrix in R?

0 Answers0