Unnatural behaviour in Pickling

[Pekka Niiranen]

Hi there,

why must file be opened in "r" -mode, before loading works
with Pickling? This forces me to close the file between pickle.dump
and pickle.load. :(

Example:
-----************------

a = {'pekka': 1, 'jussi': 2}
fh = open('c:\temp\log.log', "wb")
pickle.dump(a,fh)
fh.close()

**** now:
fh = open('c:\temp\log.log', "wb")
b = pickle.load(fh)
**** gives error:
IOError: (0, 'Error')

**** however:
fh = open('c:\temp\loglog', "rb")
b = pickle.load(fh)
**** works.

-pekka-

[Reinhold Birkenfeld]

Pekka Niiranen wrote:

Hi there,

why must file be opened in "r" -mode, before loading works
with Pickling? This forces me to close the file between pickle.dump
and pickle.load. :(

Example:
-----************------

a = {'pekka': 1, 'jussi': 2}
fh = open('c:\temp\log.log', "wb")
pickle.dump(a,fh)
fh.close()

**** now:
fh = open('c:\temp\log.log', "wb")
b = pickle.load(fh)
**** gives error:
IOError: (0, 'Error')

**** however:
fh = open('c:\temp\loglog', "rb")
b = pickle.load(fh)
**** works.

Well, unpickling involves reading from the file, so you must open it in
read and write mode, e.g. "w+b".
BTW, you should reset the file pointer between dumping and loading by
using seek().

Reinhold

--
Wenn eine Linuxdistribution so wenig brauchbare Software wie Windows
mitbrächte, wäre das bedauerlich. Was bei Windows der Umfang eines
"kompletten Betriebssystems" ist, nennt man bei Linux eine Rescuedisk.
-- David Kastrup in de.comp.os.unix.linux.misc