Is there a way to save the state of a class??

[Alex Martelli]

"EdwardT" <edwardt at trillium.com> wrote in message
news:9bpra9$q0l at news.or.intel.com...
> Hello, I current have a script that do certain processing on files, and
> requires user to enter certain info such as:
> 1. inputfile name
> 2. output file name
> 3. whether it would like process all files recusively or just one (stored
as
> a Int instance in class, value got from CheckButton widget in runtime )
> 4. a string that supplies the protocol stack it is building. (stored as a
> string instance in class)

By "in class" I guess you mean, as an attribute in an instance
of some class?

>
> Instead of writing some code to save all these some sort of  text file;
and
> re-read the next time ithe script got invoked.  Does python offer the
option
> to save the state of the whole script, as some kind of persistence
objects?

"The state of the whole script" would be more of a problem -- isn't it
enough to save the state of an instance, as you ask before and in the
subject (assuming that's what you mean by 'state of a class')?

Standard module pickle does that (and cPickle does it, too, but
faster).  Here's a simple example -- assume the following is
scriptfile flup.py:

import sys, cPickle

class Words:
    def __init__(self, *words):
        self.words = words

if len(sys.argv)>1:
    # build and persist an object
    obj = Words(*sys.argv[1:])
    cPickle.dump(obj, open("flup.dat","wb"))
else:
    # depersist and display an object
    obj = cPickle.load(open("flup.dat","rb"))
    for word in obj.words:
        print word,
    print

An example usage might be:

D:\ian>python flup.py be bop blippo

D:\ian>python flup.py
be bop blippo

D:\ian>


Lots more info, and examples of more advanced usage, are in
the standard Python library reference manual.


Alex