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.

Answer 1

A list is the most general type. You could for instance initialize “A”:

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

The pros use seq_along() instead of 1:length(.)

If they are all the same number of columns but different numbers of rows then this might work:

do.call(rbind, A)   # since "A" is a list and the natural second argument to do.call