[Python-3000] Format specifier proposal

[Ron Adam]

Greg Ewing wrote:
> Guido van Rossum wrote:
>> On 8/13/07, Andrew James Wade <andrew.j.wade at gmail.com> wrote:
>>
>>> On Mon, 13 Aug 2007 20:53:26 -0700
>>> "Guido van Rossum" <guido at python.org> wrote:
> 
>>>> I propose that their
>>>> __format__ be defined like this:
>>>>
>>>>  def __format__(self, spec):
>>>>      return self.strftime(spec)
>>> You loose the ability to align the field then.
> 
> This might be a use case for the chaining of format specs
> that Ron mentioned. Suppose you could do
> 
>    "{{1:spec1}:spec2}".format(x)
> 
> which would be equivalent to
> 
>    format(format(x, "spec1"), "spec2")


What I was thinking of was just a simple left to right evaluation order.

     "{0:spec1, spec2, ... }".format(x)

I don't expect this will ever get very long.


> then you could do
> 
>    "{{1:%Y-%m-%d %H:%M:%S}:<20}".format(my_date)
> 
> and get your date left-aligned in a 20-wide field.

So in this case all you would need is...

     {0:%Y-%m-%d %H:%M:%S,<20}



> (BTW, I'm not sure about using strftime-style formats
> as-is, since the % chars look out of place in our new
> format syntax.)
> 
> --
> Greg
> _______________________________________________
> Python-3000 mailing list
> Python-3000 at python.org
> http://mail.python.org/mailman/listinfo/python-3000
> Unsubscribe: http://mail.python.org/mailman/options/python-3000/rrr%40ronadam.com
> 
>