How to add a subkey in a nested dictionary-CodePudding

So i have a list of typles: x= [('0', '0', '20'), ('0', '0', '25'),('0', '3', '28'), ('1', '1', '74'), ('1', '1', '2')]

I want to create a nested dictionary by iterating the original (not addding them manually) to get:

dictionary= {'0': {'0': ('20', '25')},{'3': ('28')} , '1': {'1': ('74', '2')}}

In other words, in the list of tuples, group them by: the first element of the tuples being the key, the second the subkey and the third the value of the subkey.

If two tuples have the same key and subkey we add the value to the values (i.e.{'0':'0': ('20', '25')}
If they have the same key but different subkey, we add a subkey,key pair under the same key (i.e.{'0':{'0': ('20', '25')},{'3': ('28')}}

How would the code be?

CodePudding user response：

x = [('0', '0', '20'), ('0', '0', '25'),('0', '3', '28'), ('1', '1', '74'), ('1', '1', '2')]

a = {}

def add_dict2(innerdict, ele2, ele3):
    if not innerdict.get(ele2):
        innerdict[ele2] = []

    innerdict[ele2].append(ele3)

def add_dict(elel, ele2, ele3):
    if not a.get(ele1):
        a[ele1] = {}

    add_dict2(a[ele1], ele2, ele3)

for (ele1, ele2, ele3) in x:
    add_dict(ele1, ele2, ele3)

print(a)

Prints

{'0': {'0': ['20', '25'], '3': ['28']}, '1': {'1': ['74', '2']}}

CodePudding user response：

Try the following :

x = [('0','0','20'),('0','0','25'),('0','3','28'),('1','1','74'),('1','1','2')]


from collections import defaultdict
your_dict = defaultdict(dict)

for row in x:
    your_dict[row[0]][row[1]] = tuple([n for n in [r[2] for r in x if r[1] == row[1]]])

Your precise expected output:

{'0': {'0': ('20','25'), '3': ('28')}, '1': {'1': ('74','2')}})

CodePudding user response：

If you can use list instead of tuple for nested dictionary you can try this:

from collections import defaultdict

dct = defaultdict(lambda : defaultdict(list))

x= [('0', '0', '20'), ('0', '0', '25'),('0', '3', '28'), ('1', '1', '74'), ('1', '1', '2')]

for item in x:
    dct[item[0]][item[1]].append(item[2])
    
print(dct)

Output:

defaultdict(<function <lambda> at 0x7fed4026a040>, {'0': defaultdict(<class 'list'>, {'0': ['20', '25'], '3': ['28']}), '1': defaultdict(<class 'list'>, {'1': ['74', '2']})})

>>> dct['0']
defaultdict(list, {'0': ['20', '25'], '3': ['28']})

>>> dct['0']['0']
['20', '25']

>>> dct['1']
defaultdict(list, {'1': ['74', '2']})

>>> dct['1']['1']
['74', '2']