collections 模块之Counter

from collections import Counter

users = ["body1","body11","body13","body14","body11","body12","body13","body11"]

user_counter = Counter(users)

print (user_counter)　　　　

#打印结果:
Counter({‘body11‘: 3, ‘body13‘: 2, ‘body1‘: 1, ‘body14‘: 1, ‘body12‘: 1})


user1_counter = Counter("abcdABCDAAccDd")　　　　#统计字符串
print (user1_counter)

#打印结果：
Counter({‘c‘: 3, ‘A‘: 3, ‘d‘: 2, ‘D‘: 2, ‘a‘: 1, ‘b‘: 1, ‘B‘: 1, ‘C‘: 1})

user1_counter.update(user_counter)　　　　#更新合并统计（将user_counter和user1_counter的数据合并统计）
print (user1_counter)

#打印结果：
Counter({‘c‘: 3, ‘A‘: 3, ‘body11‘: 3, ‘d‘: 2, ‘D‘: 2, ‘body13‘: 2, ‘a‘: 1, ‘b‘: 1, ‘B‘: 1, ‘C‘: 1, ‘body1‘: 1, ‘body14‘: 1, ‘body12‘: 1})

user1_counter.update(‘1234‘)       #合并统计（将user1_counter的数据加入1234后统计）
print (user1_counter)

打印结果：
Counter({‘c‘: 3, ‘A‘: 3, ‘body11‘: 3, ‘d‘: 2, ‘D‘: 2, ‘body13‘: 2, ‘a‘: 1, ‘b‘: 1, ‘B‘: 1, ‘C‘: 1, ‘body1‘: 1, ‘body14‘: 1, ‘body12‘: 1, ‘1‘: 1, ‘2‘: 1, ‘3‘: 1, ‘4‘: 1})

#统计出出现次数最多的前n个元素,示例打印前两个
print(user_counter.most_common(2))

#打印结果：
[(‘body11‘, 3), (‘body13‘, 2)]