python
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一、统计列表中重复项出现的次数
举例:
(1)
>>> list1 = ['a','b','a','c','a','c','b']
>>> from collections import Counter
>>> Counter(list1)
Counter({'a': 3, 'b': 2, 'c': 2})
(2)
>>> list1 = ['a', 'b', 'a', 'c', 'a', 'c', 'b']
>>> set1 = set(list1)
>>> set1
{'b', 'c', 'a'}
>>>for item in set1:
print('the %s appears %d times' %(item, list1.count(item))) # %s为字符型,%d为整型
the b appears 2 times
the c appears 2 times
the a appears 3 times
(3)
>>> list1 = ['a', 'b', 'a', 'c', 'a', 'c', 'b']
>>> a = {} #定义空字典
>>> for i in list1:
if list1.count(i)>1:
a[i] = list1.count(i) #字典a,,key是list1内的项,value是统计此项出现的次数
>>> print(a)
{'b': 2, 'c': 2, 'a': 3}
举例:
(1)
>>> list1 = ['a','b','a','c','a','c','b']
>>> from collections import Counter
>>> Counter(list1)
Counter({'a': 3, 'b': 2, 'c': 2})
(2)
>>> list1 = ['a', 'b', 'a', 'c', 'a', 'c', 'b']
>>> set1 = set(list1)
>>> set1
{'b', 'c', 'a'}
>>>for item in set1:
print('the %s appears %d times' %(item, list1.count(item))) # %s为字符型,%d为整型
the b appears 2 times
the c appears 2 times
the a appears 3 times
(3)
>>> list1 = ['a', 'b', 'a', 'c', 'a', 'c', 'b']
>>> a = {} #定义空字典
>>> for i in list1:
if list1.count(i)>1:
a[i] = list1.count(i) #字典a,,key是list1内的项,value是统计此项出现的次数
>>> print(a)
{'b': 2, 'c': 2, 'a': 3}
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