Question

I wrote this python code in an attempt to convert objects to a string of ones and zeros, but the decoding fails because the data can’t be unpickled. This is the code:

def encode(obj):
    'convert an object to ones and zeros'
    def tobin(str):
        rstr = ''
        for f in str:
            if f == "0": rstr += "0000"
            elif f == "1": rstr += "0001"
            elif f == "2": rstr += "0010"
            elif f == "3": rstr += "0100"
            elif f == "4": rstr += "1000"
            elif f == "5": rstr += "1001"
            elif f == "6": rstr += "1010"
            elif f == "7": rstr += "1100"
            elif f == "8": rstr += "1101"
            elif f == "9": rstr += "1110"
            else: rstr += f
        return rstr
    import pickle, StringIO
    f = StringIO.StringIO()
    pickle.dump(obj, f)
    data = f.getvalue()
    import base64
    return tobin(base64.b16encode(base64.b16encode(data)))
def decode(data):
    def unbin(data):
        rstr = ''
        for f in data:
            if f == "0000": rstr += "0"
            elif f == "0001": rstr += "1"
            elif f == "0010": rstr += "2"
            elif f == "0100": rstr += "3"
            elif f == "1000": rstr += "4"
            elif f == "1001": rstr += "5"
            elif f == "1010": rstr += "6"
            elif f == "1100": rstr += "7"
            elif f == "1101": rstr += "8"
            elif f == "1110": rstr += "9"
        return rstr
    import base64
    ndata = base64.b16decode(base64.b16decode(unbin(data)))
    import pickle, StringIO
    f = StringIO.StringIO(ndata)
    obj = pickle.load(f)
    return obj

Answer 1

I think there are several problems, but one is that when you decode, you need to iterate through groups of 4 characters in you unbin() function, not single characters like you are currently doing.