Move data from specific row from one column to the adjacent row to the next column in R

I have a data frame with three columns:

df <- data.frame(col1=c('71711', '71711',  '71711', 'Comment 4', '71711', 'Comment 6'),
                  col2=c('Comment 1','Comment 2','Comment 3', '24','Comment 5','26'),
                  col3 = c('21','22','23',NA,'25',NA))

Desired output:

Col1    Col2   Col3
71711   Comment 1   21
71711   Comment 2   22
71711   Comment 3   23
71711   Comment 4   24
71711   Comment 5   25
71711   Comment 6   26

I tried the following but it replaces desired values with numeric one:

for (i in 1:nrow(df))
  {
  
  if  (any(sapply(df$col2, is.numeric)) == "True" )
       df$col3[i] <- df$col2[i]
       df$col1[i] <- df$col2[i]

}

Thanks

>Solution :

You can find rows which have NA in col3 and just ‘shift’ values:

indices <- which(is.na(df$col3))
df[indices,] <- append(list(paste0("ID", indices)), df[indices,-3])