How can I create an ordered dictionary from json in Python

Question

I am posting the form and then grabbing the json to form the dict .

myd = \
{'a': {'b': 'c1', 'd': 'f1'},
 'b': {'bb': 'c2', 'dd': 'f2'},
 'c': {'bbb': 'c3', 'ddd': 'f3'}
}

Now I am using josn.loads to convert that into python dict

I am doing this

        headers = DefaultOrderedDict(list, json.loads(request.POST.get('myd')))

Can I do an ordered, default dict in Python?

after doing that my order of the dict gets changed like this

  myd = \
    {'a': {'b': 'c1', 'd': 'f1'},
     'c': {'bbb': 'c3', 'ddd': 'f3'},
     'b': {'bb': 'c2', 'dd': 'f2'},
}

How can I maintain the order?

You probably just need a `sorted` call somewhere ... where do you get `DefaultOrderedDict` from?! — wim, May 03 '13 at 02:19
. I don't want to sort by any key but i just want to have the same order as original That came from here http://stackoverflow.com/questions/6190331/can-i-do-an-ordered-default-dict-in-python — user2330497, May 03 '13 at 02:22

score 4 · Accepted Answer · answered May 03 '13 at 02:29

4

I believe you should do:

json.loads(request.POST.get('myd'), object_pairs_hook=collections.OrderedDict)

You can see some documentation about the object_pairs_hook keyword in the documentation.

answered May 03 '13 at 02:29

Bill Lynch

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score 0 · Answer 2 · answered May 03 '13 at 02:28

Purpose of the python dictionary object is to provide you with O(1) access to key value pairs. As a result the dictionary may choose to arrange it in different order for better performance needs. Having said that you can always do something similar to :

for key in sorted(myd.iterkeys()):
    print "%s: %s" % (key, myd[key])

How can I create an ordered dictionary from json in Python

2 Answers2