title: How can I append to the new line of a file while using write()?
body: <p>In Python:
  Let's say I have a loop, during each cycle of which I produce a list with the following format:
  ['n1','n2','n3']
  After each cycle I would like to write to append the produced entry to a file (which contains all the outputs from the previous cycles). How can I do that?</p>
  
  <p>Also, is there a way to make a list whose entries are the outputs of this cycle? i.e.
  [[],[],[]] where each internal []=['n1','n2','n3] etc</p>