How to add elements to a list in R loop

Question

I would like to add elements to a list in a loop  I don t know exactly how many   Like this   l  lt - list    while         l  lt - new element         At the end  l 1  would be my first element  l 2  my second and so on   Do you know how to proceed

User · Answer

The following adds elements to a list in a loop   l lt -c   i 1  while i lt 100         b lt -i     l lt -c l b      i i 1

User · Answer

You should not add to your list using c inside the loop  because that can result in very very slow code  Basically when you do c l  new element   the whole contents of the list are copied  Instead of that  you need to access the elements of the list by index  If you know how long your list is going to be  it s best to initialise it to this size using l  lt - vector  list   N   If you don t you can initialise it to have length equal to some large number  e g if you have an upper bound on the number of iterations  and then just pick the non-NULL elements after the loop has finished  Anyway  the basic point is that you should have an index to keep track of the list element and add using that eg   i  lt - 1 while            l  i    lt - new element     i  lt - i   1     For more info have a look at Patrick Burns  The R Inferno  Chapter 2

[r] How to add elements to a list in R (loop)

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