[Python-Dev] PEP 292, Simpler String Substitutions

[Guido van Rossum]

> > def birth(self, name):
> >     country = self.countryOfOrigin['name']
> >     return '${name} was born in ${country}'.sub()
> 
> now explain why the above is a vast improvement over:
> 
>     def birth(self, name):
>         country = self.countryOfOrigin['name']
>         return join(name, ' was born in ', country)

One word: I18n.

> (for extra bonus, explain how sub() can be made to
> execute substantially faster than a join() function)

That's not a requirement.  It can obviously be made as fast as the %
operator.

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