from collections import namedtuple

# 定義一個表示二維坐標(biāo)點的命名元組
Point = namedtuple('Point', ['x', 'y'])
p = Point(10, y=20)
print(p.x, p.y)  # 輸出: 10 20print(p[0] + p[1])  # 輸出: 30，仍支持索引訪問

# 定義一個表示用戶信息的命名元組
User = namedtuple('User', 'name age city')
user1 = User('Alice', 30, 'Beijing')
print(f"{user1.name} lives in {user1.city}")  # 輸出: Alice lives in Beijing

from collections import deque

# 初始化一個雙端隊列
d = deque([1, 2, 3])
d.append(4)        # 右側(cè)添加元素 -> deque([1, 2, 3, 4])
d.appendleft(0)    # 左側(cè)添加元素 -> deque([0, 1, 2, 3, 4])
print(d.pop())     # 輸出: 4，從右側(cè)彈出
print(d.popleft()) # 輸出: 0，從左側(cè)彈出

# 創(chuàng)建固定長度的隊列，當(dāng)隊列滿時，添加新元素會擠出另一端元素
rolling_window = deque(maxlen=3)
for i in range(5):
    rolling_window.append(i)
    print(rolling_window)  # 輸出: deque([0], maxlen=3) -> deque([0,1], maxlen=3) -> ... -> deque([2,3,4], maxlen=3)

from collections import Counter

# 統(tǒng)計列表元素頻率
words = ['apple', 'banana', 'apple', 'orange', 'banana', 'apple']
word_counts = Counter(words)
print(word_counts)  # 輸出: Counter({'apple': 3, 'banana': 2, 'orange': 1})

# 直接統(tǒng)計字符串字符
char_counter = Counter('abracadabra')
print(char_counter.most_common(3))  # 輸出: [('a', 5), ('b', 2), ('r', 2)]，出現(xiàn)頻率最高的3個# 計數(shù)器支持數(shù)學(xué)運算
c1 = Counter(a=3, b=1)
c2 = Counter(a=1, b=2)
print(c1 + c2)   # 輸出: Counter({'a': 4, 'b': 3})
print(c1 - c2)   # 輸出: Counter({'a': 2})，只保留正數(shù)計數(shù)

from collections import defaultdict

# 值為列表的默認字典，常用于分組
group_by_length = defaultdict(list)
words = ['apple', 'bat', 'bar', 'atom', 'book']
for word in words:
    group_by_length[len(word)].append(word)
print(dict(group_by_length))  # 輸出: {5: ['apple'], 3: ['bat', 'bar', 'atom'], 4: ['book']}

# 值為整數(shù)的默認字典，用于計數(shù)（類似Counter的簡單實現(xiàn)）
count_dict = defaultdict(int)
for char in 'programming':
    count_dict[char] += 1
print(dict(count_dict))  # 輸出: {'p':1, 'r':2, 'o':1, ...}

# 使用lambda設(shè)置復(fù)雜的默認值default_with_lambda = defaultdict(lambda: '未知')
default_with_lambda['name'] = 'Alice'
print(default_with_lambda['age'])  # 輸出: '未知'，而不是引發(fā)KeyError

from collections import OrderedDict

# 創(chuàng)建有序字典
od = OrderedDict()
od['z'] = 1
od['y'] = 2
od['x'] = 3
print(list(od.keys()))  # 輸出: ['z', 'y', 'x']，保持插入順序

# 移動元素到末尾（可用于實現(xiàn)LRU緩存）
od.move_to_end('z')
print(list(od.keys()))  # 輸出: ['y', 'x', 'z']

# 相等性比較：OrderedDict會考慮順序
od1 = OrderedDict([('a', 1), ('b', 2)])
od2 = OrderedDict([('b', 2), ('a', 1)])
print(od1 == od2)  # 輸出: False，因為順序不同