On Jul 20, 9:27 am, Phillip B Oldham <phillip.old...@gmail.com> wrote: > Specifically the "differences" between lists and tuples have us > confused and have caused many "discussions" in the office. We > understand that lists are mutable and tuples are not, but we're a > little lost as to why the two were kept separate from the start. They > both perform a very similar job as far as we can tell.
The underlying C code for the two is substantially the same. In terms of code, tuples are in effect just immutable lists that have the added feature of being hashable (and therefore usable as dictionary keys or elements of sets). Beyond the mutable/hashable distinction, there is an important philosophical distinction articulated by Guido. He deems tuples to be useful for struct like groupings of non-homogenous fields and lists to be useful for sequences of homogenous data suitable for looping. While nothing in the list/tuple code requires you to make that distinction, it is important because that philosophy pervades the language. If you follow Guido's direction, you'll find that the various parts of the language fit together better. Do otherwise and you'll be going against the grain. Raymond P.S. The C code for lists and tuples have a slightly difference internal structure that makes tuples a little more space efficient (since their size is known at the outset and doesn't change during use). -- http://mail.python.org/mailman/listinfo/python-list
