CODEWITHSUNDEEP
pythondictionarynesteddel
anonymous.kim
anonymous.kim

Reputation: 3

How to delete a element from nested dictionary?

I have a dictionary that like this :

card_pool = {
    'ace' : [1,11], 
    '2' : 2,
    '3' : 3,
    '4' : 4,
    '5' : 5,
    '6' : 6,
    '7' : 7,
    '8' : 8,
    '9' : 9,
    '10' : 10,
    'J' : 10,
    'Q' : 10,
    'K' : 10,
}

l_card_pool = {}
l_card_pool['spade'] = card_pool
l_card_pool['clover'] = card_pool
l_card_pool['heart'] = card_pool
l_card_pool['diamond'] = card_pool

I wanted to delete a key-value pair of :

l_card_pool['spade']['ace']

So I used :

del l_card_pool['spade']['ace']

What I've expected of print(l_card_pool) is this :

{
'spade': {'2': 2, '3': 3, '4': 4, '5': 5, '6': 6, '7': 7, '8': 8, '9': 9, '10': 10, 'J': 10, 'Q': 10, 'K': 10}, 
'clover': {'ace': [1, 11], '2': 2, '3': 3, '4': 4, '5': 5, '6': 6, '7': 7, '8': 8, '9': 9, '10': 10, 'J': 10, 'Q': 10, 'K': 10}, 
'heart': {'ace': [1, 11], '2': 2, '3': 3, '4': 4, '5': 5, '6': 6, '7': 7, '8': 8, '9': 9, '10': 10, 'J': 10, 'Q': 10, 'K': 10}, 
'diamond': {'ace': [1, 11], '2': 2, '3': 3, '4': 4, '5': 5, '6': 6, '7': 7, '8': 8, '9': 9, '10': 10, 'J': 10, 'Q': 10, 'K': 10}
}

But I actually got this :

{
'spade': {'2': 2, '3': 3, '4': 4, '5': 5, '6': 6, '7': 7, '8': 8, '9': 9, '10': 10, 'J': 10, 'Q': 10, 'K': 10}, 
'clover': {'2': 2, '3': 3, '4': 4, '5': 5, '6': 6, '7': 7, '8': 8, '9': 9, '10': 10, 'J': 10, 'Q': 10, 'K': 10}, 
'heart': {'2': 2, '3': 3, '4': 4, '5': 5, '6': 6, '7': 7, '8': 8, '9': 9, '10': 10, 'J': 10, 'Q': 10, 'K': 10}, 
'diamond': {'2': 2, '3': 3, '4': 4, '5': 5, '6': 6, '7': 7, '8': 8, '9': 9, '10': 10, 'J': 10, 'Q': 10, 'K': 10}
}

There is a way of deleting only l_card_pool['spade']['ace'] ?

Whole code is this :

card_pool = {
    'ace' : [1,11], 
    '2' : 2,
    '3' : 3,
    '4' : 4,
    '5' : 5,
    '6' : 6,
    '7' : 7,
    '8' : 8,
    '9' : 9,
    '10' : 10,
    'J' : 10,
    'Q' : 10,
    'K' : 10,
}

l_card_pool = {}
l_card_pool['spade'] = card_pool
l_card_pool['clover'] = card_pool
l_card_pool['heart'] = card_pool
l_card_pool['diamond'] = card_pool >create l_card_pool dictionary

print(l_card_pool) 

del l_card_pool['spade']['ace'] >What I used to delete a element from nested dictionary

print(l_card_pool)

Upvotes: 0

Views: 59

Answers (2)

AveragePythonEnjoyer
AveragePythonEnjoyer

Reputation: 1165

You are assigning each key in your card pool dictionary the same dictionary (card pool). Although you have four keys thy still refer to the same dictionary.

If you want to create a new instance of the dictionary card pool, you will have to initiate a new object. You can do this in different ways, the easiest for you is probably to use .copy() on the dict you want to copy:

card_pool = {
    'ace' : [1,11], 
    '2' : 2,
    '3' : 3,
    '4' : 4,
    '5' : 5,
    '6' : 6,
    '7' : 7,
    '8' : 8,
    '9' : 9,
    '10' : 10,
    'J' : 10,
    'Q' : 10,
    'K' : 10,
}

l_card_pool = {}
l_card_pool['spade'] = card_pool.copy()
l_card_pool['clover'] = card_pool.copy()
l_card_pool['heart'] = card_pool.copy()
l_card_pool['diamond'] = card_pool.copy()

print(l_card_pool) 

del l_card_pool['spade']['ace']

print(l_card_pool)

As a general advice for a python newbie from a python newbie, if you don't see any () you are referring to an old\existing object.

Upvotes: 0

bereal
bereal

Reputation: 34282

All dicts l_card_pool[*] are the same dict. If you're planning to mutate any of them, you need to copy them on creation, e.g.:

l_card_pool = {}
for suite in ('spade', 'clover', 'heard', 'diamond'):
    l_card_pool[suite] = card_pool.copy()

That creates a shallow copy of the dict. If for any reason, you're planning to mutate e.g. l_card_pool['spade']['ace'] by removing elements from it, I'd suggest using deepcopy.

Upvotes: 1

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