[Python-3000] PEP 3113 (Removal of Tuple Parameter Unpacking)

[Ka-Ping Yee]

On 3/4/07, Raymond Hettinger <python at rcn.com> wrote:
> FWIW, I would like the feature to be kept.  I've found it useful in that it
> documents the function signature more completely when dealing
> with arguments that are already pre-packed into tuples

I just noticed that this has a more noticeable effect on lambda, since
you don't have room for another statement to do the unpacking.

To sort a dictionary by value, you can currently write

    sorted(dict.items(), key=lambda (key, value): value)

Without tuple unpacking, this idiom becomes

    sorted(dict.items(), key=lambda item: item[1])

obscuring the fact that the item is a (key, value) pair.


-- ?!ng