Data frame Q

Dear Group,
Kindly,
 I have the following 

Common_Friends <- intersect(node_neighbours_i_out,node_neighbours_j_out)
         class(Common_Friends)
         print(Common_Friends)
         #4 = Common_Friends
       newline<-c(i,   Common_Friends  )
 df<- rbind(df,newline)

I created a data frame to add the new line

when   Common_Friends  =0 nothing add ?, how to force it to write the value into the data frame


Common_Friends <- intersect(node_neighbours_i_out,node_neighbours_j_out)

         class(Common_Friends)

[1] "numeric"

         print(Common_Friends)

numeric(0)

       newline<-c(i,   Common_Friends  )
newline

[1] 5
thanks in advance
Ragia