[Python-Dev] Re: PEP 292, Simpler String Substitutions

[Guido van Rossum]

> Have you considered the possibility of accepting keyword arguments
> instead?  They would be slightly more pleasant to write:
> 
>         print s.sub(name='Guido', country='the Netherlands')
> 
> This is motivated because i imagine relative frequencies of use
> to be something like this:
> 
>     1.  sub()                      [most frequent]
>     2.  sub(name=value, ...)       [nearly as frequent]
>     3.  sub(dictionary)            [least frequent]
> 
> If you decide to use keyword arguments, you can either allow both
> keyword arguments and a single dictionary argument, or you can
> just accept keyword arguments and people can pass in dictionaries
> using **.

I imagine that the most common use case is a situation where the dict
is already prepared.  I think **dict is slower than a positional dict
argument.  I agree that keyword args would be useful in some cases
where you can't trust the string.

--Guido van Rossum (home page: http://www.python.org/~guido/)