Most elegant ways to add a few empty rows into a data frame in R?

Question

This is an example of what I want to do:

df <- data.frame(x=1:100,y=1:100)
empty_row_ids <- c(5,10)

This is the final output:

results <- rbind(data.frame(x=1:4,y=1:4),c(0,0),data.frame(x=5:8,y=5:8),c(0,0).data.frame(x=9:100,y=9:100)) 

Essentially, I want to insert some empty rows at some given numbers.

Answer 1

A way to do what you want would be formating the empty_rows_id inside a dataframe with the zeroes and then use bind_rows() in a dplyr pipeline to add the data. Here the code:

library(dplyr)
#Data
df <- data.frame(x=1:100,y=1:100)
empty_row_ids <- c(5,10)
#Create data for rows
dfindex <- data.frame(id=empty_row_ids,x=0,y=0)
#Now bind
df2 <- df %>% mutate(id=1:n()) %>%
  bind_rows(dfindex) %>%
  arrange(id) %>% select(-id)

Output (some rows):

      x   y
1     1   1
2     2   2
3     3   3
4     4   4
5     5   5
6     0   0
7     6   6
8     7   7
9     8   8
10    9   9
11   10  10
12    0   0
13   11  11
14   12  12
15   13  13

If you want to export to other source to format your tables, it would be better to use NA instead of zero as @MrFlick said.

Answer 2

I'd recommend looking for a formatting solution, rather than one that changes your data. But you can use add_row() to do what you're asking.

library(dplyr)

n <- 2 # number of spacing rows to insert at each point
spacer <- rep("", n)

df %>%
  mutate(across(.fns = as.character)) %>%
  add_row(x = spacer, y = spacer, .before = 6) %>%
  add_row(x = spacer, y = spacer, .before = 11) 

Output:

      x   y
1     1   1
2     2   2
3     3   3
4     4   4
5          
6          
7     5   5
8     6   6
9     7   7
10         
11         
12    8   8
13    9   9
14   10  10
...

Insert as many spacing rows n as you desire with rep("", n) at the target indices.

Answer 3

Here's a base R solution

add_empty_rows <- function(df, at) {
  new_len <- nrow(df) + length(at)
  result <- as.data.frame(lapply(df, function(x) vector(class(x), new_len)))
  result[(1:new_len)[-at],] <- df
  result
}
newdf <- add_empty_rows(df, empty_row_ids)

Basically we just make a new data.frame with all blank rows, then put the values we want to keep in the slots we don't want to keep empty

Answer 4

Here is one way manipulating row index :

inds <- seq(nrow(df))
df1 <- df[c(inds  - cumsum(inds %in% empty_row_ids), 
            tail(inds, length(empty_row_ids))), ]

row.names(df1) <- NULL
df1[empty_row_ids, ] <- 0
df1

#      x   y
#1     1   1
#2     2   2
#3     3   3
#4     4   4
#5     0   0
#6     5   5
#7     6   6
#8     7   7
#9     8   8
#10    0   0
#11    9   9
#12   10  10
#13   11  11
#..
#..
#99   97  97
#100  98  98
#101  99  99
#102 100 100