計數器 Counter 計數元素迭代器 elements() 計數對象拷貝 copy() 計數對象清空 clear() 有序字典 OrderedDict (對字典的補充,可以記住字典元素添加的順序) 預設字典 defaultdict,(指定字典值的類型) 可命名元組 namedtuple (給元組對 ...
計數器 Counter
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計數元素迭代器 elements()
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計數對象拷貝 copy()
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計數對象清空 clear()
from collections import Counter
#import collections
d = Counter("abdadakdabfdj") #對值計數,返回一個對象
print(d, type(d)) #Counter({'a': 4, 'd': 4, 'b': 2, 'k': 1, 'f': 1, 'j': 1}) <class 'collections.Counter'>
print(list(d), type(d)) #['a', 'b', 'd', 'k', 'f', 'j'] <class 'collections.Counter'>
print(dict(d), type(d)) #{'a': 4, 'b': 2, 'd': 4, 'k': 1, 'f': 1, 'j': 1} <class 'collections.Counter'>
print(d.elements()) #elements()方法返回一個迭代器,內容為進行計數的元素
for i in d.elements():
print(i) # a a a a d d d d b b k f j
d1 = d.copy()
print(d1,type(d1)) #Counter({'a': 4, 'd': 4, 'b': 2, 'k': 1, 'f': 1, 'j': 1}) <class 'collections.Counter'>
d2 = d.subtract("aaa")
print(d2,type(d2))
d3 = d.update('aaa')
print(d3,type(d3))
d4 = d.pop("j")
print(d4,d) # 1 Counter({'a': 4, 'd': 4, 'b': 2, 'k': 1, 'f': 1})
d.clear() # clear()方法清空計數的元素\
print(d) # Counter()
有序字典 OrderedDict (對字典的補充,可以記住字典元素添加的順序)
from collections import OrderedDict order_dict = OrderedDict() print(order_dict,type(order_dict)) order_dict["c"] = 94 order_dict["b"] = 92 order_dict["d"] = 95 order_dict["a"] = 90 print(order_dict,type(order_dict)) #返回有序字典對象,OrderedDict([('c', 94), ('b', 92), ('d', 95), ('a', 90)]) <class 'collections.OrderedDict'> print(dict(order_dict),type(order_dict))#{'c': 94, 'b': 92, 'd': 95, 'a': 90} <class 'collections.OrderedDict'> print(list(order_dict),type(order_dict))#['c', 'b', 'd', 'a'] <class 'collections.OrderedDict'> print(order_dict.popitem()) #提取出字典的最後一個鍵值對 ('a', 90) print(order_dict) #OrderedDict([('c', 94), ('b', 92), ('d', 95)]) print(order_dict.pop("b")) #提取出字典指定鍵對應的值 print(order_dict) #OrderedDict([('c', 94), ('d', 95)]) order_dict.move_to_end("c") #將指定的鍵值對移動到最後 print(order_dict) #OrderedDict([('d', 95), ('c', 94)])
預設字典 defaultdict,(指定字典值的類型)
from collections import defaultdict
default_dict = defaultdict(list) # 指定字典的值類型為列表
print(default_dict,type(default_dict)) #defaultdict(<class 'list'>, {}) <class 'collections.defaultdict'>
for i in range(10):
default_dict["a"].append(i)
print(default_dict) #defaultdict(<class 'list'>, {'a': [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]})
可命名元組 namedtuple (給元組對應的值起個對應的名字,相當於字典)
from collections import namedtuple
tuple1 = namedtuple("tuple_name",["name","age","school","adress"])
print(tuple1)
tuple1 = tuple1("xu",20,"jinggangshan","jiangxi")
print(tuple1.name)