Inserting a new row to data frame for each group id

Question

I\'ve looked extensively on stack overflow for a solution, but have yet to find one that works for me. I have a data frame that looks something like this:

id         


        

Answer 1

Using dplyr

   library(dplyr)

 # data:   
    df <- structure(list(id = structure(c(1L, 1L, 2L, 2L, 3L, 3L), .Label = c("A", 
    "B", "C"), class = "factor"), time = structure(c(3L, 4L, 1L, 
    2L, 5L, 6L), .Label = c("10:56", "10:57", "11:10", "11:11", "4:30", 
    "4:31"), class = "factor"), latitude = c(381746, 381726.2, 381703, 
    381679.7, 381654.4, 381629.2), longitude = c(6008345L, 6008294L, 
    6008214L, 6008134L, 6008083L, 6008033L)), .Names = c("id", "time", 
    "latitude", "longitude"), row.names = c(NA, -6L), class = c("tbl_df", 
    "tbl", "data.frame"))

 # code: 

    df %>% group_by(id) %>% 
        do({ df <- . 
             last_row           <- df %>% slice(n())
             last_row$latitude  <- 394681.4
             last_row$longitude <- 6017550
             df                 <- bind_rows(df, last_row)
        })