trying to learn shelving keep getting an error

[aeristh]

Input:

import pickle, shelve
 
variety = ["sweet", "hot", "dill"]
shape = ["whole", "spear", "chip"]
brand = ["Claussen", "Heinz", "Vlassic"]
f = open("pickles2.db", "wb")
pickle.dump(variety, f)
pickle.dump(shape, f)
pickle.dump(brand, f)
f.close()
 
f = open("pickles2.db", "rb")
variety = pickle.load(f)
shape = pickle.load(f)
brand = pickle.load(f)
 
print(variety)
print(shape)
print(brand)
f.close()
 
print("\nShelving lists.")
s = shelve.open("pickles2.db")

Output error in idle:

Traceback (most recent call last):
File "C:/Python33/pickling 2.py", line 23, in <module>
s = shelve.open("pickles2.db")
File "C:\Python33\lib\shelve.py", line 232, in open
return DbfilenameShelf(filename, flag, protocol, writeback)
File "C:\Python33\lib\shelve.py", line 216, in __init__
Shelf.__init__(self, dbm.open(filename, flag), protocol, writeback)
File "C:\Python33\lib\dbm\__init__.py", line 83, in open
raise error[0]("db type could not be determined")
dbm.error: db type could not be determined

Prints that after outputting everything until after:
print("\nShelving lists.")

I'm very new go easy on me.

[bvdet]

From the Python docs: "A “shelf” is a persistent, dictionary-like object." The data you are attempting to shelve is not a dictionary.

[dwblas]

f = open("pickles2.db", "rb")
variety = pickle.load(f)
shape = pickle.load(f)
brand = pickle.load(f)
 
s = shelve.open("pickles2.db") 

The pickles2.db file can only be one type, pickle, shelve, text, etc. If you change the name of one of the files, then the program runs, i.e. you are not trying to open a pickle file using shelve.

Shelve create file example: http://pymotw.com/2/shelve/
Pickle create file example: http://pymotw.com/2/pickle/index.html