Op Thursday 30 Apr 2015 14:28 CEST schreef Peter Otten: > Cecil Westerhof wrote: > >>> (2) you may want to take measures to limit memory usage, e. g. >>> >>> assert index >= 0 >> >> I put that in, but as first statement. > > For the record, this was not a recommended check, but rather a way > to communicate to the reader of my code that unlike yours it doesn't > support negative indices. > >>> try: >>> [line] = itertools.islice(f, index, index+1) >>> except ValueError: >>> raise IndexError >>> return line.rstrip() >> >> In my case it is not important. (The biggest file I use has between >> 100 and 200 lines), but I publish it, so I should do my best to >> make it so lean as possible. > > If you keep your > > return f.readlines()[index] > > anyway you might allow for negative indices, and then > > get_indexed_message(message_filename, -1) > > fetches the last message in the file and > > get_indexed_message(message_filename, slice(None, None)) > > fetches a list with all messages.
It is even possible without keeping it. I can fetch the number of messages and implement it myself without a possible high memory overhead. Certainly something to think about. -- Cecil Westerhof Senior Software Engineer LinkedIn: http://www.linkedin.com/in/cecilwesterhof -- https://mail.python.org/mailman/listinfo/python-list
