On 2007-08-07, Steven W. Orr <[EMAIL PROTECTED]> wrote:
> I have a structure I need to pack. I call struct.pack about a dozen times
> and each call takes about 53 arguments.
>
> I create a sequence of the arguments:
> a1 = 1
> a2 = 2
> a3 = 3
> etc...
> a54 = 88
> myseq = (a1, a2, a3, a4 etc... a53)
> Also I made
>
> def mpack ( fmt, *ss ):
> print type(ss)
> for ii in ss:
> print 'ii = ', ii, 'type(ii) = ', type(ii)
> for ii in list(ss):
> print 'ii = ', ii, 'type(ii) = ', type(ii)
> return struct.pack(fmt, *ss )
>
> In my main, this first print statement works.
> print 'main:', mpack(ff, a, b, c, d, e, f, g, h, i)
>
> 1. For the life of me, I can't figure out what to do to get the
> next print to work. The idea is that I want to make my code
> clearer by not passing 50+ args each time and to instead pass a
> sequence which when evaluated will be the desired list of args.
>
> print 'main:', mpack(ff, subseq)
>
> 2. And then, if possible, I'd like to do it in such a way that
> one myseq is defined, its value can automagically be re-eval'd
> so I don't have to re-assign to myseq each time one of the 50+
> variables changes prior to calling pack.
A functor might be a fun solution.
class mpack_maker(object):
def __init__(self, fmt, *args):
self.fmt = fmt
self.arg_list = list(args)
def __call__(self, slice=None, subseq=None):
if slice:
self.arg_list[slice] = subseq
return struct.pack(self.fmt, *self.arg_list)
You can pass in a slice object and a subsequence to change
arguments (permanently).
>>> mpack = mpack_maker(ff, a, b, c, d, e, f, g, h)
>>> mpack() # Call the function
>>> mpack(slice(5, 7), [0, 7]) # Change args 5 and 6, and call again.
The args you can change are limited by the slicing powers of
Python, and probably combining arg-changing with calling the
function isn't wise, but that's a sketch anyhow.
--
Neil Cerutti
We couldn't beat... us. We couldn't even beat us. I was trying to think of
somebody bad, and I couldn't think of anybody else. Us. --Tim Legler
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