[Christoph Zwerschke] > And can somebody explain what is exactly meant with > "homogenous data"?
This seems to have been explained a few times recently :) Basically, if you have a "list of xs" and remove one item from it, it is still a "list of xs", where "xs" might be people, coordinate-pairs, numbers or whatever made sense to you. If you have a tuple containing, say, a 2d coordinate pair, and remove something from it, it's no longer a coordinate pair. If you add one to it, it's something else as well (perhaps a 3d coord?) A typical example of their combined use is a set of rows returned from a database: each row is a tuple of fields, the same as all other such rows, and removing or adding a field would make no sense. However, add a new row to the list and it remains a list of rows. Now you can take this or leave it within Python. You can but mixed values into a list so it isn't really a list of "xs" unless "x" is just "thing". Likewise you can use a tuple to hold a list of identical things although you can't add to it or take away. > Concretely speaking, which data type should I use > for coordinate tuples? Usually, tuples are used. Does this mean that I > should better use lists from now on because all the components have the > same type? This would seem to be slightly false logic (and very possibly used tongue-in-cheek). Heterogeneous data doesn't mean that each item *has* to be different, merely that they *may* be. TJG -- http://mail.python.org/mailman/listinfo/python-list
