adding fields to picked structures
Bob van der Poel
bvdpoel at uniserve.com
Mon Dec 25 13:09:28 EST 2000
I've got a little database which I read/write using cpickle. Now, I want
to add a field to my database. The old one might be:
class Mydata:
def __init__(self, ...)
foo=''
bar=''
...
Now, a list of Mydata's has been saved to a file.
Later, I decide that I need to add another field, say 'newdata'. So, I
modify the class definition and try to read my data.
So, far all is good...until I try to access 'newdata'. If it's a new
record (not read in by pickle) all is okay, but if I try to access
'newdata' in an existing record I get
TypeError: attribute-less object (assign or del)
So, I suppose I could write a conversion utility...but, I'd like to
avoid that if possible. Am I missing something...or is this just the way
life should be?
--
Bob van der Poel ** Wynndel, British Columbia, CANADA **
EMAIL: bvdpoel at uniserve.com
WWW: http://users.uniserve.com/~bvdpoel
More information about the Python-list
mailing list