[SciPy-user] How to read legacy scipy.Pickler arrays?

[Robert Kern]

On Mon, Mar 24, 2008 at 4:56 PM, Mark Coletti <mcoletti at gmail.com> wrote:

> Ok, I give up.  What do I need to do to read legacy scipy pickled data?

Here is the relevant code from old Numeric. It should be
straightforward to update for numpy.

def DumpArray(m, fp):
    if m.typecode() == 'O':
        raise TypeError, "Numeric Pickler can't pickle arrays of Objects"
    s = m.shape
    if LittleEndian: endian = "L"
    else: endian = "B"
    fp.write("A%s%s%d " % (m.typecode(), endian, m.itemsize()))
    for d in s:
        fp.write("%d "% d)
    fp.write('\n')
    fp.write(m.tostring())

def LoadArray(fp):
    ln = string.split(fp.readline())
    if ln[0][0] == 'A': ln[0] = ln[0][1:] # Nasty hack showing my
ignorance of pickle
    typecode = ln[0][0]
    endian = ln[0][1]

    shape = map(lambda x: string.atoi(x), ln[1:])
    itemsize = string.atoi(ln[0][2:])

    sz = reduce(multiply, shape)*itemsize
    data = fp.read(sz)

    m = fromstring(data, typecode)
    m = reshape(m, shape)

    if (LittleEndian and endian == 'B') or (not LittleEndian and endian == 'L'):
        return m.byteswapped()
    else:
        return m

import pickle, copy
class Unpickler(pickle.Unpickler):
    def load_array(self):
        self.stack.append(LoadArray(self))

    dispatch = copy.copy(pickle.Unpickler.dispatch)
    dispatch['A'] = load_array

class Pickler(pickle.Pickler):
    def save_array(self, object):
        DumpArray(object, self)

    dispatch = copy.copy(pickle.Pickler.dispatch)
    dispatch[ArrayType] = save_array


-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless
enigma that is made terrible by our own mad attempt to interpret it as
though it had an underlying truth."
 -- Umberto Eco