Python容器資料類型——collections

#!/usr/bin/python#coding=utf-8#http://docs.python.org/library/collections.html#count對象 Only 2.7from collections import Counter#統計字母出現的次數Counter('hello world')  Counter(['red', 'blue', 'red', 'green', 'blue', 'blue']) #小於等於0的會被忽略c = Counter(a=4, b=2, c=0, d=-2)list(c.elements())#取前三個最多的字母Counter('hello world').most_common(3) #堆from collections import dequed = deque('abc')d.append('d')d.pop() #後入先出d.popleft() #先入先出#返回最後n行文本deque(open(filename), n)#defaultdictfrom collections import defaultdict#使用list初始化一個dictd = defaultdict(list)d["yellow"].append(1)d["red"].append(2)d["yellow"].append(3)print d.items() #[('red', [2]), ('yellow', [1, 3])]#用int初始華一個dictd = defaultdict(int)d["yellow"] += 1d["red"] += 2d["yellow"] += 3print d.items() #[('red', 2), ('yellow', 4)]