Making string-formatting smarter by handling generators?

[Gabriel Genellina]

En Wed, 27 Feb 2008 14:23:49 -0200, Tim Chase  
<python.list at tim.thechases.com> escribi�:

> Is there an easy way to make string-formatting smart enough to
> gracefully handle iterators/generators?  E.g.
>
>    transform = lambda s: s.upper()
>    pair = ('hello', 'world')
>    print "%s, %s" % pair # works
>    print "%s, %s" % map(transform, pair) # fails
>
> with a """
> TypeError:  not enough arguments for format string
> """

Note that your problem has nothing to do with map itself. String  
interpolation using % requires either many individual arguments, or a  
single *tuple* argument. A list is printed as itself.

py> "%s, %s" % ['hello', 'world']
Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
TypeError: not enough arguments for format string
py> "%s" % ['hello', 'world']
"['hello', 'world']"

So the answer is always use tuple(...) as others pointed.

-- 
Gabriel Genellina