On Sun, 17 Apr 2005 19:56:10 -0700, Brian Sabbey
<[EMAIL PROTECTED]> wrote:
>I also wouldn't do it that way. I don't see a class as being much better,
>though. If I understand you correctly, with classes you would have
>something like:
>
>p = Pickled('pickled.txt')
>p.load()
>p.data.append('more data')
>p.data.append('even more data')
>p.dump()
The load and dump would be private to the data class object. Here's a
more complete example.
import pickle
class PickledData(object):
def __init__(self, filename):
self.filename = filename
self.L = None
try:
self._load()
except IOError:
self.L = []
def _load(self):
f = open(self.filename, 'r')
self.L = pickle.load(f)
f.close()
def _update(self):
f = open(self.filename, 'w')
pickle.dump(self.L, f)
f.close()
def append(self, record):
self.L.append(record)
self._update()
# add other methods as needed ie.. get, sort, clear, etc...
pdata = PickledData('filename')
pdata.append('more data')
pdata.append('even more data')
print pdata.L
['more data', 'even more data']
>This has the same issues as with opening and closing files: losing the
>'dump', having to always use try/finally if needed, accidentally
>re-binding 'p', significantly more lines. Moreover, class 'Pickled' won't
>be as readable as the 'pickled_file' function above since 'load' and
>'dump' are separate methods that share data through 'self'.
A few more lines to create the class, but it encapsulates the data
object better. It is also reusable and extendable.
Cheers,
Ron
>The motivation for thunks is similar to the motivation for generators--
>yes, a class could be used instead, but in many cases it's more work than
>should be necessary.
>
>-Brian
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