Cannot load pickled object

The problem I am having is when I try to load the pickled object. I have tried using both pickle.loads and pickle.load Here are the results:

pickle.loads:

TypeError: 'str' does not support the buffer interface

pickle.load:

TypeError: file must have 'read' and 'readline' attributes

Can someone please tell me what I am doing wrong in this process?

elif str(parser) == "SwissWithdrawn_Parser": # swissprot name changes print("Gathering SwissProt update info...") cache_hits = 0 cache_misses = 0 files = set() for f in os.listdir("out/cache/"): if os.path.isfile("out/cache/" + f): files.add(f) for name in sp_lost_names: cached = False url = ( "" + name + "+active%3ayes&format=tab&columns=entry%20name" ) hashed_url = str(hash(url)) ################### For Testing Only - use cache ################## if hashed_url in files: cached = True cache_hits += 1 content = pickle.loads("out/cache/" + hashed_url) # <-- problematic line else: cache_misses += 1 content = urllib.request.urlopen(url) # get the contents returned from the HTTPResponse object content_list = [x.decode().strip() for x in content.readlines()] if not cached: with open("out/cache/" + hashed_url, "wb") as fp: pickle.dump(content_list, fp) #################################################################### # no replacement if len(content_list) is 0: change_log["swiss-names"] = {name: "withdrawn"} # get the new name else: new_name = content_list[1] change_log["swiss-names"] = {name: new_name}

2 Answers

You need to either read the file first (as binary bytes) and use pickle.loads(), or pass an open file object to the pickle.load() command. The latter is preferable:

with open('out/cache/' +hashed_url, 'rb') as pickle_file: content = pickle.load(pickle_file)

Neither method supports loading a pickle from a filename.

If you happen to be porting python2 to 3 and run into this error, python2 and 3 handle bytes different leading to the requirement to open your file handle with the 'b' option. For instance in python2 open(file, 'r') as f: my_list = pickle.load(f) works , but not in python3. Instead you must open with open(file, 'rb') as f: my_list = pickle.load(f)