R - Save Full Data Sets

Question

When i am using loop in R, for example

for (k in 1:length(bcd)) {
  print(window(abc,start = (as.Date(start[i,]),end = (as.Date(finish[i,]))))
}

The outcome will be the the full selected data.

However, if i want to save the selected data, it only remember the data corresponding to last loop counter.

for (k in 1:length(bcd)) {
  A = ???(window(abc,start = (as.Date(start[i,]),end = (as.Date(finish[i,]))))
}

What is the right function to use in "???" ? Thanks.