創建帶有值的字典時，將值任意從 False 更改為 True

Question

有必要形成一個字典作為參數，其中有一組字典。 在這些詞典中，有一個名為“reverse”的鍵。 默認情況下，此鍵設置為 False。 添加字典時，我會根據某些條件更改“反向”鍵的值。 但不知為何，在一般的源詞匯中，“逆”的意思只變到了Pravda。

為什么意思隨意變化，在什么地方？

# -*- coding: utf-8 -*-

struct_state_devices = None
dict_gate = {"state_gate": {},
             "position": {"state": "", "stop": False},
             "reverse": False,
             }
test_list = [{"device_code": "1111", "reverse": False}, {"device_code": "2222", "reverse": True}]

if struct_state_devices is None:
    struct_state_devices = dict()
for dev in test_list:
    struct_state_devices[dev["device_code"]] = dict_gate  # добавление словаря устройства

print("before: " + str(struct_state_devices))

for dev in test_list:
    if dev["reverse"] is True:
        struct_state_devices[dev["device_code"]]["reverse"] = True
        # print(self.struct_state_devices[dev.device_code]['reverse'])
print("after: " + str(struct_state_devices))

輸出：

before: {'1111': {'state_gate': {}, 'position': {'state': '', 'stop': False}, 'reverse': False}, '2222': {'state_gate': {}, 'position': {'state': '', 'stop': False}, 'reverse': False}}
after: {'1111': {'state_gate': {}, 'position': {'state': '', 'stop': False}, 'reverse': True}, '2222': {'state_gate': {}, 'position': {'state': '', 'stop': False}, 'reverse': True}}

Answer 1

您正在將對象dict_gate分配給您的 dict 鍵struct_state_devices[dev['device_code']] 。 當您將該對象內的某個值更改為某個其他值時，您也在為所有其他值更改它。

試試這個：

for dev in test_list:
    struct_state_devices[dev["device_code"]] = dict_gate.copy()

明白了嗎：

>>> for dev in test_list:
    struct_state_devices[dev['device_code']] = dict_gate

>>> id(dict_gate)
1267141041832
>>> id(struct_state_devices['1111'])
1267141041832

>>> for dev in test_list:
    struct_state_devices[dev['device_code']] = dict_gate.copy()

>>> id(struct_state_devices['1111'])
1267141285912
>>> id(struct_state_devices['2222'])
1267141286232

請注意使用dict_gate而不是dict_gate.copy()時的 ID