Trailing comma (was: Re: structure in Python)

[Peter Hansen]

Cousin Stanley wrote:
> 
> >>>
> >>> x = [ 'fe' , 'fi' 'fo' , 'fum' , ]
> >>>
> >>> print "we have", len(x), "thingies"
> we have 3 thingies
> 
> Alex ....
> 
>   I don't understand how an extra comma at the end
>   of a sequence is supposed to help with problems
>   like this where a sequence delimeter, the comma,
>   has been ommitted in the middle of the sequence ....

Note that Alex' list was not all on one line, as you have
reformatted it above.  In such a case, I would not include
the trailing comma.

In the case of lists formatted with one item per line, I 
now always include the trailing comma for just the maintenance
reasons Alex mentions.  This is certainly a case where I've
been burned often enough in (older) C because you *could not*
do that, and I'm happy to have it in Python and, now, in C.

-Peter