R adding columns and data

Question

I have a table with two columns A and B. I want to create a new table with two new columns added: X and Y. These two new columns are to contain data from column A, but every second row from column A. Correspondingly for column X, starting from the first value in column A and from the second value in column A for column Y.

So far, I have been doing it in Excel. But now I need it in R best function form so that I can easily reuse that code. I haven't done this in R yet, so I am asking for help.

Example data:

structure(list(A = c(2L, 7L, 5L, 11L, 54L, 12L, 34L, 14L, 10L, 
6L), B = c(3L, 5L, 1L, 21L, 67L, 32L, 19L, 24L, 44L, 37L)), class = "data.frame", row.names = c(NA, 
-10L))

Sample result:

structure(list(A = c(2L, 7L, 5L, 11L, 54L, 12L, 34L, 14L, 10L, 
6L), B = c(3L, 5L, 1L, 21L, 67L, 32L, 19L, 24L, 44L, 37L), X = c(2L, 
NA, 5L, NA, 54L, NA, 34L, NA, 10L, NA), Y = c(NA, 7L, NA, 11L, 
NA, 12L, NA, 14L, NA, 6L)), class = "data.frame", row.names = c(NA, 
-10L))

Answer 1

It is not a super elegant solution, but it works:

exampleDF <- structure(list(A = c(2L, 7L, 5L, 11L, 54L, 
                                  12L, 34L, 14L, 10L, 6L), 
                            B = c(3L, 5L, 1L, 21L, 67L, 
                                  32L, 19L, 24L, 44L, 37L)), 
                       class = "data.frame", row.names = c(NA, -10L))

index <- seq(from = 1, to = nrow(exampleDF), by = 2)

exampleDF$X <- NA
exampleDF$X[index] <- exampleDF$A[index]

exampleDF$Y <- exampleDF$A
exampleDF$Y[index] <- NA