"shelve" save object

[hypermonkey2]

Hi there!
I am using the "shelve" module in a script to save information in
between runtime sessions of the program. (its a sort of
data collector, so its important to hold on to anything computed ).
In any case, I shelve into a file "test.txt". I notice that when i try
running the program on a different computer (by either emailing or
transfering the file "test.txt" via USB key), the program is unable to
load the shelve file.
What can I do to fix this? It would be a great shame to see that after
collecting all this information and shelving it that I cannot move to
another computer or share the information through the "save.txt" file.

Thanks in advance!
Jon

 

[John Machin]

Hi there!
I am using the "shelve" module in a script to save information in
between runtime sessions of the program. (its a sort of
data collector, so its important to hold on to anything computed ).
In any case, I shelve into a file "test.txt". I notice that when i try
running the program on a different computer (by either emailing or
transfering the file "test.txt" via USB key), the program is unable to
load the shelve file.
What can I do to fix this? It would be a great shame to see that after
collecting all this information and shelving it that I cannot move to
another computer or share the information through the "save.txt" file.

For a start, you could consider telling us what "unable to load the
shelve file" means ... please copy any error message, exception
information and traceback and paste it into your response. Showing the
code that deals with the shelf file would also be useful; we don't
want to guess what your shelve.open args are.

.... "on a different computer": How many different computers? How many
times? To check the possibility that the file was mangled in transit
between computers, have you compared the filesize and md5 checksum
before and after transport?

When asking questions like this, it's a very good idea to state what
computer platform, what version of what OS, and what version of
Python. In your case, you need to report this info for both the
creating computer and the unable-to-load computers(s).

Try this on both the creating computer and the unable-to-load
computers(s), at the Python interactive prompt:

and report the results.

Also consider changing the name from "test.txt" to something
meaningful -- a file with a ".txt" extension is just begging silly
software and silly humans to treat it as a text file and mangle it.

HTH,
John

 

[alex23]

In any case, I shelve into a file "test.txt". I notice that when i try
running the program on a different computer (by either emailing or
transfering the file "test.txt" via USB key), the program is unable to
load the shelve file.

You might find the 3rd party module 'shove' is more suitable for your
needs here.

http://pypi.python.org/pypi/shove

It provides a lot more backend support than shelve, of particular
interest to you would be filesystem (& maybe sqlite).

from shove import Shove
fsdb = Shove('file://persistent.db')
fsdb['key1'] = 'value1'
fsdb.close()

In this example, using the file protocol will produce a
'persistent.db' folder with the key/value pairs stored within it as
files. This should be cross platform enough for your needs.