from collections import namedtuple, deque, Counter, OrderedDict # 创建一个新class Point, 有两个属性 x y Point = namedtuple('Point', ['x', 'y', 'z']) p = Point(1, 1, 3) print(p.x) print(p.y) print(p.count(1)) d = p._asdict() # 转换dict print(d['x']) d['x'] = 3 print(d['x']) print(p.x) # deque python中双向列表, 删除和插入速度快, list索引快,但是删除和插入慢 a = deque('abc') print(a) # deque对象为可迭代对象 for cha in a: print(cha) # 尾部插入插入元素 a.append('d') a.extend(('e', 'f', 'g')) print(a) # 首部插入元素 a.appendleft(1) a.extendleft((4, 3, 2)) # 注意左边插入可迭代对象时,顺序是反的,出入的值是[2, 3, 4] print(a) # 删除元素 a.pop() a.popleft() print(a) # Counter() 统计字符串字符出现的次数 s = 'programping' c = Counter() for ch in s: c[ch] = c[ch] + 1 print(c) print(c['p']) print(c['d']) # OrderDict按键的插入顺序排序 order_dict = OrderedDict() order_dict['x'] = 1 order_dict['z'] = 2 order_dict['c'] = 3 order_dict['b'] = 4 order_dict['a'] = 4 print(order_dict) for k, v in order_dict.items(): print(k, v)
python--常用库collections
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