What is the syntax rule for having trailing commas in tuple definitions?

Question

In the case of a single element tuple, the trailing comma is required.

a = (\'foo\',)

What about a tuple with multiple elements? It seems t

Answer 1

Also, consider the situation where you want:

>>> (('x','y'))*4                         # same as ('x','y')*4
('x', 'y', 'x', 'y', 'x', 'y', 'x', 'y')
#Expected = (('x', 'y'), ('x', 'y'), ('x', 'y'), ('x', 'y'))

So in this case the outer parentheses are nothing more than grouping parentheses. To make them tuple you need to add a trailing comma. i.e.

>>> (('x','y'),)*4 
(('x', 'y'), ('x', 'y'), ('x', 'y'), ('x', 'y'))