String formatters with variable argument length

[Peter Otten]

John Machin wrote:

>> > Fredrik Tolf wrote:

>> > > The thing is, I want to get format strings from the user, and I don't
>> > > want to require the user to consume all the arguments.

> what's ugly about this:
> [untested]:
> 
> def count_format_args(s):
>     pending = False
>     count = 0
>     for c in s:
>         if c == "%":
>             # doubled % chars aren't counted
>             pending = not pending
>         elif pending:
>             count += 1
>             pending = False
>     return count
> 
> output = format % arglist[:count_format_args(format)]

Keep in mind, though, that it doesn't take '*' into account:

>>> count_format_args("%*.*f")
1
>>> "%*.*f" % (3,2,1)
'1.00'

And just because I don't think I've seen it before:

>>> count_format_args("%42%")
1
>>> "%42%" % ()
'                                         %'

Peter