"Roel Schroeven" <rschroev_nospam...@fastmail.fm> wrote
In the point of view taken by Guido and the writer of the blogs
mentioned before, a tuple of x, y coordinates is not homogeneous,
it's
heterogeneous. Both x and y do have the same type, but that's not
the
point. The point is that the meaning of the two elements is
different.
It makes, for example, no sense to sort such a tuple.
Yes, I spotted Guido making that point shortly after posting :-)
I guess its more a case of thinking of tuples as lightweight records
rather that strictly heterogenuous(*) types (which is a somewhat moot
issue in Python). So the significant point is that in a tuple each
"field"
has a meaning specific to its position.
The big problem is that they are also immutable which greatly
reduces their effectiveness in that role. So the alternatives are
create
a class - for possibly a single instance - or use a list as a writable
record.
(*) Although heterogenuous does not really debar same type
items but the focus on type is I suspect misleading in terms of
understanding the role of tuples.
--
Alan Gauld
Author of the Learn to Program web site
http://www.freenetpages.co.uk/hp/alan.gauld
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