Why tuple with one item is no tuple

[James Stroud]

On Tuesday 15 March 2005 08:25 am, Roy Smith wrote:
> a = ()       # tuple of zero elements
> a = (1,)     # tuple of one element
> a = 1,       # tuple of one element
> a = (1)      # scalar
> a = (1, 2)   # tuple of two elements
> a = 1, 2     # tuple of two elements
> a = ,        # syntax error
>
> The big question is, is it the parens that make it a tuple, or is it
> the comma?  If you go along with the parens school of thought, then
> (1,) is the special case.  If you believe in commas, then the () is
> the special case.  In either case, it's a bit ugly, but we learn to
> overlook the occasional cosmetic blemishes of those we love :-)

The answer is obvious, the naked comma should be an empty tuple.


-- 
James Stroud, Ph.D.
UCLA-DOE Institute for Genomics and Proteomics
Box 951570
Los Angeles, CA 90095