original = ([1, 2], [3, 4])  # 元組包含列表
new_list = list(original)    # 轉(zhuǎn)為列表

new_list[0].append(99)       # 修改內(nèi)部列表
print(original) 
# ? 輸出: ([1, 2, 99], [3, 4]) 
# 解釋：原元組里的列表也被改了！因為指向同一內(nèi)存地址。

data = [3, 1, 4, 1, 5]
unique_data = list(set(data))
print(unique_data) 
# ? 陷阱：你以為結(jié)果是 [3, 1, 4, 5] (保持原序去重)
# ? 實際結(jié)果可能是 [1, 3, 4, 5] 或其他任意順序

# ? 正確做法：保持順序去重
seen = set()
unique_ordered = [x for x in data if not (x in seen or seen.add(x))]
# 或者 Python 3.7+ 利用 dict 保序特性
unique_ordered = list(dict.fromkeys(data))

data = [[1, 2], [3, 4]]
# set(data)  # ? TypeError: unhashable type: 'list'

# ? 解決：先將內(nèi)部列表轉(zhuǎn)為元組
set(tuple(x) for x in data) 

user = {"name": "Alice", "age": 25}
lst = list(user)
print(lst) 
# ? 輸出: ['name', 'age'] (只有鍵！)

# ? 想要值
list(user.values()) # ['Alice', 25]
# ? 想要鍵值對
list(user.items())  # [('name', 'Alice'), ('age', 25)]

# ? 錯誤：元素長度不對
data = [("a", 1, "extra")]
dict(data) # ValueError: dictionary update sequence element #0 has length 3; 2 is required

# ? 錯誤：單個值不是對
data = ["a", "b"]
dict(data) # ValueError: dictionary update sequence element #0 has length 1; 2 is required

# ? 正確
data = [("a", 1), ("b", 2)]
dict(data)

data = [("a", 1), ("a", 2), ("a", 3)]
d = dict(data)
print(d) # {'a': 3} (1 和 2 丟失了)

s = {'a', 'b'}
# dict(s) # ? ValueError: dictionary update sequence element #0 has length 1; 2 is required

# ? 正確：初始化為空值或特定值
d = {k: None for k in s} 

data = [3, 1, 2, 1, 5, 3]
unique_data = list(dict.fromkeys(data))
# 結(jié)果: [3, 1, 2, 5]

keys = ['name', 'age', 'city']
values = ['Alice', 25, 'Beijing']
user = dict(zip(keys, values))
# 結(jié)果: {'name': 'Alice', 'age': 25, 'city': 'Beijing'}

list_a = [1, 2, 3, 4]
list_b = [3, 4, 5, 6]

# 找 A 有但 B 沒有的
diff = list(set(list_a) - set(list_b)) 
# 結(jié)果可能是 [1, 2] (順序不定)

# 如果需要有序結(jié)果
diff_sorted = sorted(set(list_a) - set(list_b))
# 結(jié)果: [1, 2]

original = {'a': 1, 'b': 2, 'c': 1}
# ? 直接互換會丟失 'a' 或 'c'
swapped = {v: k for k, v in original.items()}
# 結(jié)果: {1: 'c', 2: 'b'} ('a' 被 'c' 覆蓋了)

# ? 如果值有重復(fù)，需要轉(zhuǎn)為列表
from collections import defaultdict
reverse_map = defaultdict(list)
for k, v in original.items():
    reverse_map[v].append(k)
# 結(jié)果: {1: ['a', 'c'], 2: ['b']}