On Feb 27, 4:23 pm, Tim Chase <[EMAIL PROTECTED]> wrote:
> 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
> """
>
> I can force it by wrapping the results of my generator in a call
> to tuple() or list()
(Are you using python 3.0 ? For python < 3, map returns a list)
list() wouldn't work as % expects a tuple (otherwise it considers that
only one argument is needed). The problem would arise with any non-
tuple iterable, not just generators.
See http://docs.python.org/lib/typesseq-strings.html
>
> print "%s, %s" % tuple(map(transform, pair))
>
> but it feels a bit hackish to me.
I think it is the way to do it though.
> I find I hit it mostly with calls to map() where I want to apply
> some transform (as above) to all the items in a list of
> parameters such as
>
> "%s=%s&%s=%s" % map(urllib.quote, params)
>
> Any suggestions? (even if it's just "get over your hangup with
> wrapping the results in list()/tuple()" :)
get over your hangup with wrapping the results in tuple()! (not list()
though, as explained above).
Or you could always define
def tmap(*args):
return tuple(map(*args))
--
Arnaud
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