counter计数器

import collections as con

st = ‘1324243598234598756‘
tup = (4,67,7,5,6,67,78,8,4,2,2,4,
       4,56,7,8,5,3,23,45,468,9,1,)
lis = [1,4,5,7,8,2,2,1,56,7,89,34,2,3,4,5,6,5,8,7,4,12,1]

# 计算序列某元素出现的次数
ret = con.Counter(st)
print(ret,‘str‘)
ret = con.Counter(tup)
print(ret,‘tuple‘)
ret = con.Counter(lis)
print(ret,‘list‘)

# 取最多出现的元素,参数为取前几个
ret1 = ret.most_common(5)
print(ret,ret1,‘most_common‘)

# 循环取排列后的所有元素
for i in ret.elements():
    print(i,‘elements‘)

# 循环取计数后的键值对(i=键,m=键值)
for i,m in ret.items():
    print(i,m,‘items()‘)

# 循环取计数后的键
for i in ret.keys():
    print(i,‘keys‘)

# 循环取计数后的键值
for i in ret.values():
    print(i,‘values‘)

# 计数一个新序列,将新计次结果和原有基础相加
ret = con.Counter(st)
ret.update(st)
print(ret,‘update‘)

# 计数一个新序列,在原有基础上减去新计次结果(如果原有基础没有新序列的某个元素,那么就是0-n)
ret = con.Counter(st)
ret.subtract(‘7asdd‘)
print(ret,‘subtract‘)