import shelve d = shelve.open(filename) # open -- file may get suffix added by low-level # library d[key] = data # store data at key (overwrites old data if # using an existing key) data = d[key] # retrieve a COPY of data at key (raise KeyError if no # such key) del d[key] # delete data stored at key (raises KeyError # if no such key) flag = d.has_key(key) # true if the key exists klist = d.keys() # a list of all existing keys (slow!) # as d was opened WITHOUT writeback=True, beware: d['xx'] = range(4) # this works as expected, but... d['xx'].append(5) # *this doesn't!* -- d['xx'] is STILL range(4)! # having opened d without writeback=True, you need to code carefully: temp = d['xx'] # extracts the copy temp.append(5) # mutates the copy d['xx'] = temp # stores the copy right back, to persist it # or, d=shelve.open(filename,writeback=True) would let you just code # d['xx'].append(5) and have it work as expected, BUT it would also # consume more memory and make the d.close() operation slower. d.close() # close it
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