On Wed, 11 Sep 2013 09:03:49 -0400, Neal Becker wrote:
> In py2.7 this was accepted, but not in py3.3. Is this intentional? It
> seems to violate the 'principle' that extraneous parentheses are usually
> allowed/ignored
>
> In [1]: p = lambda x: x
>
> In [2]: p = lambda (x): x
> File "<ipython-input-2-2b94675a98f1>", line 1
> p = lambda (x): x
> ^
> SyntaxError: invalid syntax
It is not specific to lambda, it has to do with the removal of argument
unpacking in function argument lists:
# allowed in Python 2, not in Python 3
def f(a, b, (c, d), e):
pass
In Python 3, the parser appears to disallow any extra parentheses inside
the parameter list, even if strictly speaking they don't do anything:
py> def f(a, b, (c), d, e):
File "<stdin>", line 1
def f(a, b, (c), d, e):
^
SyntaxError: invalid syntax
--
Steven
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