Tuple Syntax and ()

[tact...@gmail.com]

I keep accidently trying to declare t-tuples as mytuple = (myitem)

I know this doesn't work and that you need the trailing comma, but
reading something online, I just came to realize.... the parenthesises
don't have any special meaning in relation to tuples at all, do they?

[James Stroud]

Aside from grouping, they are special to construct an empty tuple.

py> () == tuple()
True

Also, don't underestimate their relationship with tuples when it comes
to grouping:

py> a, b, c = 1, 2, 3
py>
py> a == a, b, c
(True, 2, 3)
py> a == (a, b, c)
False

James

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James Stroud
UCLA-DOE Institute for Genomics and Proteomics
Box 951570
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http://www.jamesstroud.com/

[Steve Holden]

Give that (?)man a cigar! The only time the parentheses are necessary is
when you need to disambiguate - the most frequent needs are:

() for an empty tuple: there's no other way to express that without
using tuple(), and

f((a, b, ...)) to provide a single tuple argument to a function.

regards
Steve
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