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问题:
I want to create a function to recursively traverse a multidimensional dictionary, where the dimensions are unknown.
Here is what I have come up with so far, but it doesn't seem to be working correctly. This will print out some key / values twice and they are not in order.
def walk_dict(d): for k,v in d.items(): if isinstance(v, dict): walk_dict(v) else: print "%s %s" % (k, v)
Here's a sample array:
d = { 'plan_code': 'b', 'quantity': '1', 'account': { 'account_code': 'b', 'username': 'jdoe', 'email': 'jdoe@domain.com', 'first_name': 'b', 'last_name': 'b', 'company_name': 'Company, LLC.', 'billing_info': { 'first_name': 'b', 'last_name': 'b', 'address1': '123 Test St', 'city': 'San Francisco', 'state': 'CA', 'country': 'US', 'zip': '94105', 'credit_card': { 'number': '1', 'year': '2018', 'month': '12', 'verification_value': '123', }, }, }, }
回答1:
I'm not sure what your ultimate goal is, but the code is doing what it is supposed to. You are seeing what you think are repeats of items because there are key/value combos like 'first_name':'b' that are both within 'account' and within 'billing_info' within 'account'. I'm not sure what order you are looking for, but dictionaries are unordered so your function to print them out will have to give them some order, for instance by replacing the following:
for k,v in d.items():
with
for k,v in sorted(d.items(),key=lambda x: x[0]):
or you'll need an ordered dictionary. You can also use the pprint module like so to give a nice print out of a dict:
>>> import pprint >>> pprint.pprint(d) {'account': {'account_code': 'b', 'billing_info': {'address1': '123 Test St', 'city': 'San Francisco', 'country': 'US', 'credit_card': {'month': '12', 'number': '1', 'verification_value': '123', 'year': '2018'}, 'first_name': 'b', 'last_name': 'b', 'state': 'CA', 'zip': '94105'}, 'company_name': 'Company, LLC.', 'email': 'jdoe@domain.com', 'first_name': 'b', 'last_name': 'b', 'username': 'jdoe'}, 'plan_code': 'b', 'quantity': '1'}
However, I'm not fully sure what your end goal is here. Also, you are missing the keys when the values are dictionaries. I modified your code to do a similar thing to what pprint does in the following:
def walk_dict(d,depth=0): for k,v in sorted(d.items(),key=lambda x: x[0]): if isinstance(v, dict): print (" ")*depth + ("%s" % k) walk_dict(v,depth+1) else: print (" ")*depth + "%s %s" % (k, v)
which for your example dict yields:
>>> walk_dict(d) account account_code b billing_info address1 123 Test St city San Francisco country US credit_card month 12 number 1 verification_value 123 year 2018 first_name b last_name b state CA zip 94105 company_name Company, LLC. email jdoe@domain.com first_name b last_name b username jdoe plan_code b quantity 1
回答2:
>>> import json
>>> print json.dumps(d, indent=4)
回答3:
This does print the key, value pairs correctly. Can you point out which data gets repeated. There can be confusion based on the above data as these keys :
'first_name': 'b', 'last_name': 'b',
are part of two dictionaries - 'account' and 'billing_info'. So they will appear twice in output.
Also if you want some kind of order in which your dictionaries K,V should get printed use Ordered Dictionaries
回答4:
As Justin Peel mentions, pprint.pprint will probably do what you want.
I think the problem with your code is that you should be printing the key first before recursing, i.e. change
if isinstance(v, dict): walk_dict(v)
to
if isinstance(v, dict): print k walk_dict(v)
Though in any case it's going to look pretty confusing unless you add indentation and such.
This sort of thing is actually pretty complicated; check out the code for pprint if you want to get some ideas.
回答5:
Here is a variation on the accepted answer by Justin Peel that returns its result as an OrderedDict instead of printing the result.
from collections import OrderedDict def sort_by_keys(dct,): new_dct = OrderedDict({}) for key, val in sorted(dct.items(), key=lambda (key, val): key): if isinstance(val, dict): new_dct[key] = sort_by_keys(val) else: new_dct[key] = val return new_dct
回答6:
your code works perfect fine, it does exactly what you told it to.
The only repeats i see in the output are first_name and last_name which are in fact defined twice (in different dictionaries).
As to 'out of order' Its a dictionary, it doesn't have a guaranteed order. well maybe it does, but it would be based on the internal representation, which you shouldn't rely on.
What you need to do is sort the data in the way that you want it to come out. You also may want to print out the sub dictionary's key value to make the output easier to understand.
回答7:
In Python, dictionaries are indexed by keys. Keys can be any immutable type like a string or number. Unless the keys are sorted, they will always be returned in an arbitrary order. Because of this fact, your walk_dict is printing seemingly random results.
Here is an example of walk_dict which prints all keys and values. I've sorted they keys at each level of the dictionary. Also, I printed each key. Your code didn't print a key before it recursed. Finally, I've added string padding to emphasize each level of the dictionary. The doctests are all passing. I hope this helps you build your final function.
import doctest def walk_dict(seq, level=0): """Recursively traverse a multidimensional dictionary and print all keys and values. >>> d = {'dog': 'dusty', 'cat': 'fluffy', 'bird': 'chirpy'} >>> walk_dict(d) bird chirpy cat fluffy dog dusty >>> d = {'location': 'home', 'animals':{'dog': 'dusty', 'cat': 'fluffy', 'bird': 'chirpy'}} >>> walk_dict(d) animals bird chirpy cat fluffy dog dusty location home >>> d = {'location': 'home', 'animals':{'dog': 'dusty', 'cat': 'fluffy', 'bird': {'name':'chirpy', 'color':'blue'}}} >>> walk_dict(d) animals bird color blue name chirpy cat fluffy dog dusty location home >>> d = { \ 'plan_code': 'b', \ 'quantity': '1', \ 'account': { \ 'account_code': 'b', \ 'username': 'jdoe', \ 'email': 'jdoe@domain.com', \ 'first_name': 'b', \ 'last_name': 'b', \ 'company_name': 'Company, LLC.', \ 'billing_info': { \ 'first_name': 'b', \ 'last_name': 'b', \ 'address1': '123 Test St', \ 'city': 'San Francisco', \ 'state': 'CA', \ 'country': 'US', \ 'zip': '94105', \ 'credit_card': { \ 'number': '1', \ 'year': '2018', \ 'month': '12', \ 'verification_value': '123', \ }, \ }, \ }, \ } >>> walk_dict(d) account account_code b billing_info address1 123 Test St city San Francisco country US credit_card month 12 number 1 verification_value 123 year 2018 first_name b last_name b state CA zip 94105 company_name Company, LLC. email jdoe@domain.com first_name b last_name b username jdoe plan_code b quantity 1 """ items = seq.items() items.sort() for v in items: if isinstance(v[1], dict): # Print the key before make a recursive call print "%s%s" % (" " * level, v[0]) nextlevel = level + 1 walk_dict(v[1], nextlevel) else: print "%s%s %s" % (" " * level, v[0], v[1]) if __name__ == '__main__': doctest.testmod()
