dump a multi dimensional dictionary

[cerr]

Hi,

Can I somehow use pickle.dump() to store a dictionary of lists to a file?
I tried this:

import pickle
mylist = []
mydict = {}
mylist = '1','2'
mydict['3'] = mylist
fhg = open ("test", 'w')
pickle.dump(fhg,mydict)

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib/python2.7/pickle.py", line 1370, in dump
Pickler(file, protocol).dump(obj)
File "/usr/lib/python2.7/pickle.py", line 203, in __init__
self.write = file.write
AttributeError: 'dict' object has no attribute 'write'{'3': ('1', '2')}

or should I just write my own dump function that can hanle thiS?

Please advise!

Thanks,
Ron

 

[Prasad, Ramit]

Hi,

Can I somehow use pickle.dump() to store a dictionary of lists to a file?
I tried this:

import pickle
mylist = []
mydict = {}
mylist = '1','2'
mydict['3'] = mylist
fhg = open ("test", 'w')
pickle.dump(fhg,mydict)

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib/python2.7/pickle.py", line 1370, in dump
Pickler(file, protocol).dump(obj)
File "/usr/lib/python2.7/pickle.py", line 203, in __init__
self.write = file.write
AttributeError: 'dict' object has no attribute 'write'{'3': ('1', '2')}

or should I just write my own dump function that can hanle thiS?

Please advise!

Thanks,
Ron

I think you have the parameters for dump backwards.

According to API http://docs.python.org/2/library/pickle.html#pickle.dump
the format is: pickle.dump(obj, file, protocol=None)

Which means you need to use: pickle.dump(mydict, fhg)


Ramit



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[John Gordon]

Can I somehow use pickle.dump() to store a dictionary of lists to a file?
I tried this:

import pickle
mylist = []
mydict = {}
mylist = '1','2'
mydict['3'] = mylist
fhg = open ("test", 'w')
pickle.dump(fhg,mydict)

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib/python2.7/pickle.py", line 1370, in dump
Pickler(file, protocol).dump(obj)
File "/usr/lib/python2.7/pickle.py", line 203, in __init__
self.write = file.write
AttributeError: 'dict' object has no attribute 'write'{'3': ('1', '2')}

or should I just write my own dump function that can hanle thiS?

I think you have the arguments to pickle.dump() in the wrong order.
The data to be dumped should come first, then the file object.

 

[Chris Angelico]

mylist = []
mydict = {}
mylist = '1','2'

Side point: mylist is no longer a list, it's a tuple. I don't think
pickle has problems with tuples, but it's worth noting that
difference.

ChrisA

 

[Steven D'Aprano]

or should I just write my own dump function that can hanle thiS?

Please advise!

Given the choice between reading the documentation to pickle.dump:

help(pickle.dump)


or spending the next month writing a replacement for pickle, testing it,
debugging it, going through revision after revision to try to bring it to
the same level of maturity as pickle, which would you prefer?