python3 deque(双向队列)

创建双向队列

import collections
d = collections.deque()

append(往右边添加一个元素)

import collections
d = collections.deque()
d.append(1)
d.append(2)
print(d) #输出:deque([1, 2])

appendleft(往左边添加一个元素)

import collections
d = collections.deque()
d.append(1)
d.appendleft(2)
print(d) #输出:deque([2, 1])

clear(清空队列)

import collections
d = collections.deque()
d.append(1)
d.clear()
print(d) #输出:deque([])

copy(浅拷贝)

import collections
d = collections.deque()
d.append(1)
new_d = d.copy()
print(new_d) #输出:deque([1])

count(返回指定元素的出现次数)

import collections
d = collections.deque()
d.append(1)
d.append(1)
print(d.count(1)) #输出:2

extend(从队列右边扩展一个列表的元素)

import collections
d = collections.deque()
d.append(1)
d.extend([3,4,5])
print(d) #输出:deque([1, 3, 4, 5])

extendleft(从队列左边扩展一个列表的元素)

import collections
d = collections.deque()
d.append(1)
d.extendleft([3,4,5])
print(d)
#
# #输出:deque([5, 4, 3, 1])

index(查找某个元素的索引位置)

import collections
d = collections.deque()
d.extend(['a','b','c','d','e'])
print(d)
print(d.index('e'))
print(d.index('c',0,3)) #指定查找区间 #输出:deque(['a', 'b', 'c', 'd', 'e'])
#
#

insert(在指定位置插入元素)

import collections
d = collections.deque()
d.extend(['a','b','c','d','e'])
d.insert(2,'z')
print(d) #输出:deque(['a', 'b', 'z', 'c', 'd', 'e'])

pop(获取最右边一个元素,并在队列中删除)

import collections
d = collections.deque()
d.extend(['a','b','c','d','e'])
x = d.pop()
print(x,d) #输出:e deque(['a', 'b', 'c', 'd'])

popleft(获取最左边一个元素,并在队列中删除)

import collections
d = collections.deque()
d.extend(['a','b','c','d','e'])
x = d.popleft()
print(x,d) #输出:a deque(['b', 'c', 'd', 'e'])

remove(删除指定元素)

import collections
d = collections.deque()
d.extend(['a','b','c','d','e'])
d.remove('c')
print(d) #输出:deque(['a', 'b', 'd', 'e'])

reverse(队列反转)

import collections
d = collections.deque()
d.extend(['a','b','c','d','e'])
d.reverse()
print(d) #输出:deque(['e', 'd', 'c', 'b', 'a'])

rotate(把右边元素放到左边)

import collections
d = collections.deque()
d.extend(['a','b','c','d','e'])
d.rotate(2) #指定次数,默认1次
print(d) #输出:deque(['d', 'e', 'a', 'b', 'c'])
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