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I have nested dictionaries:
{'key0': {'attrs': {'entity': 'p', 'hash': '34nj3h43b4n3', 'id': '4130'},
u'key1': {'attrs': {'entity': 'r',
'hash': '34njasd3h43b4n3',
'id': '4130-1'},
u'key2': {'attrs': {'entity': 'c',
'hash': '34njasd3h43bdsfsd4n3',
'id': '4130-1-1'}}},
u'key3': {'attrs': {'entity': 'r',
'hash': '34njasasasd3h43b4n3',
'id': '4130-2'},
u'key4': {'attrs': {'entity': 'c',
'hash': '34njawersd3h43bdsfsd4n3',
'id': '4130-2-1'}},
u'key5': {'attrs': {'entity': 'c',
'hash': '34njawersd3h43bdsfsd4n3',
'id': '4130-2-2'}}}},
'someohterthing': 'someothervalue',
'something': 'somevalue'}
given an id - one of all the ids like 4130 to 4130-2-2.
whats the easiest way to navigate to the correct dictionary?
If the given id is 4130-2-1 then it should reach the dictionary with key=key5.
No XML approaches please.
Edit(1): The nesting is between 1 to 4 levels, but I know the nesting before I parse.
Edit(2): Fixed the code.
Edit(3): Fixed code again for string values of ids. Please excuse for the confusion created. This is final I hope :)
567
To simply check if a key exists in a Python dictionary you can use the in operator to search through the dictionary keys like this: pets = {'cats': 1, 'dogs': 2, 'fish': 3} if 'dogs' in pets: print('Dogs found!') # Dogs found! A dictionary can be a convenient data structure for counting the occurrence of items.
You can iterate through a Python dictionary using the keys(), items(), and values() methods. keys() returns an iterable list of dictionary keys. items() returns the key-value pairs in a dictionary. values() returns the dictionary values.
If you want to find the key by the value, you can use a dictionary comprehension to create a lookup dictionary and then use that to find the key from the value.
1) Using OrderedDict() and items() method Later you make use of a reversed() function which is an in-built python method that takes an argument as the sequence data types like tuple, lists, dictionaries, etc and returns the reverse of it. Remember that reversed() method does not modify the original iterator.
If you want to solve the problem in a general way, no matter how many level of nesting you have in your dict, then create a recursive function which will traverse the tree:
def traverse_tree(dictionary, id=None):
for key, value in dictionary.items():
if key == 'id':
if value == id:
print dictionary
else:
traverse_tree(value, id)
return
>>> traverse_tree({1: {'id': 2}, 2: {'id': 3}}, id=2)
{'id': 2}
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