title: why "for line in file" is more memory efficient than "readline()"?
body: <p><a href="https://i.stack.imgur.com/eVXcq.png" rel="nofollow noreferrer">As is written in python docs</a></p>
  <p><a href="https://docs.python.org/3.5/tutorial/inputoutput.html#methods-of-file-objects" rel="nofollow noreferrer">See also the original python docs</a></p>