Python – Counter.items()、Counter.keys() 和 Counter.values()
计数器类是 Python3 中的集合模块提供的一种特殊类型的对象数据集。 Collections 模块为用户提供了专门的容器数据类型，因此，提供了 Python 通用内置函数（如字典、列表和元组）的替代方案。 Counter 是一个子类，用于对可散列对象进行计数。它在调用时隐式创建一个可迭代的哈希表。
Counter.items()
Counter.items() 方法有助于查看列表中的元素以及它们在元组中各自的频率。
Syntax : Counter.items()
Parameters : None
Returns : object of class dict_items
例子 ：
Python3
# importing the module
from collections import Counter
# making a list
list = [1, 1, 2, 3, 4, 5,
6, 7, 9, 2, 3, 4, 8]
# instantiating a Counter object
ob = Counter(list)
# Counter.items()
items = ob.items()
print("The datatype is "
+ str(type(items)))
# displaying the dict_items
print(items)
# iterating over the dict_items
for i in items:
print(i)Python3
# importing the module
from collections import Counter
# making a list
list = [1, 1, 2, 3, 4, 5,
6, 7, 9, 2, 3, 4, 8]
# instantiating a Counter object
ob = Counter(list)
# Counter.keys()
keys = ob.keys()
print("The datatype is "
+ str(type(keys)))
# displaying the dict_items
print(keys)
# iterating over the dict_items
for i in keys:
print(i)Python3
# importing the module
from collections import Counter
# making a list
list = [1, 1, 2, 3, 4, 5,
6, 7, 9, 2, 3, 4, 8]
# instantiating a Counter object
ob = Counter(list)
# Counter.values()
values = ob.values()
print("The datatype is "
+ str(type(values)))
# displaying the dict_items
print(values)
# iterating over the dict_items
for i in values:
print(i)输出 ：
The datatype is
dict_items([(1, 2), (2, 2), (3, 2), (4, 2), (5, 1), (6, 1), (7, 1), (9, 1), (8, 1)])
(1, 2)
(2, 2)
(3, 2)
(4, 2)
(5, 1)
(6, 1)
(7, 1)
(9, 1)
(8, 1)
计数器.keys()
Counter.keys() 方法有助于查看列表中的唯一元素。
Syntax : Counter.keys()
Parameters : None
Returns : object of class dict_items
例子 ：
Python3
# importing the module
from collections import Counter
# making a list
list = [1, 1, 2, 3, 4, 5,
6, 7, 9, 2, 3, 4, 8]
# instantiating a Counter object
ob = Counter(list)
# Counter.keys()
keys = ob.keys()
print("The datatype is "
+ str(type(keys)))
# displaying the dict_items
print(keys)
# iterating over the dict_items
for i in keys:
print(i)
输出 ：
The datatype is
dict_keys([1, 2, 3, 4, 5, 6, 7, 9, 8])
1
2
3
4
5
6
7
9
8
Counter.values()
Counter.values() 方法有助于查看每个唯一元素的频率。
Syntax : Counter.values()
Parameters : None
Returns : object of class dict_items
例子 ：
Python3
# importing the module
from collections import Counter
# making a list
list = [1, 1, 2, 3, 4, 5,
6, 7, 9, 2, 3, 4, 8]
# instantiating a Counter object
ob = Counter(list)
# Counter.values()
values = ob.values()
print("The datatype is "
+ str(type(values)))
# displaying the dict_items
print(values)
# iterating over the dict_items
for i in values:
print(i)
输出 ：
The datatype is
dict_values([2, 2, 2, 2, 1, 1, 1, 1, 1])
2
2
2
2
1
1
1
1
1