Python3 deque (bidirectional queue)

Create a two-way queue

Import= Collections.deque ()

Append (add an element to the right)

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

Appendleft (add an element to the left)

Import= collections.deque () d.append (1) d.appendleft (2)print (d) # output: Deque ([2, 1])

Clear (Empty queue)

Import= collections.deque () d.append (1) d.clear ()print(d)  # output: deque ([])

Copy (shallow copy)

Import= collections.deque () d.append (1= d.copy ()print(new_d )# output: Deque ([1])

Count (returns the number of occurrences of the specified element)

Import= collections.deque () d.append (1) d.append (1)Print (D.count (1))# output: 2

Extend (extends the element of a list from the right side of the queue)

Import= collections.deque () d.append (1) d.extend ([3,4,5])print (d) # output: Deque ([1, 3, 4, 5])

Extendleft (extends the element of a list from the left side of the queue)

Import= collections.deque () d.append (1) d.extendleft ([3,4,5]) Print (d) ## #输出: Deque ([5, 4, 3, 1])

Index (Find the index position of an element)

ImportCOLLECTIONSD=Collections.deque () d.extend (['a','b','C','D','e'])Print(d)Print(D.index ('e'))Print(D.index ('C', 0, 3))#Specify a search interval#output: deque ([' A ', ' B ', ' C ', ' d ', ' e '])#4#   2

Insert (Inserts an element at the specified location)

ImportCOLLECTIONSD=Collections.deque () d.extend (['a','b','C','D','e']) D.insert (2,'Z')Print(d)#output: deque ([' A ', ' B ', ' Z ', ' C ', ' d ', ' e '])

Pop (Gets the rightmost element and deletes it in the queue)

ImportCOLLECTIONSD=Collections.deque () d.extend (['a','b','C','D','e']) x=D.pop ()Print(x,d)#output: E deque ([' A ', ' B ', ' C ', ' d '])

Popleft (Gets the leftmost element and deletes it in the queue)

ImportCOLLECTIONSD=Collections.deque () d.extend (['a','b','C','D','e']) x=D.popleft ()Print(x,d)#output: A deque ([' B ', ' C ', ' d ', ' e '])

Remove (removes the specified element)

ImportCOLLECTIONSD=Collections.deque () d.extend (['a','b','C','D','e']) D.remove ('C')Print(d)#output: deque ([' A ', ' B ', ' d ', ' e '])

Reverse (queue reversal)

 import   COLLECTIONSD  = Collections.deque () d.extend ([ "  a  , "  b  , "  c  , "  d  , "  e   " ]) D.reverse ()  print   (d)  #   output: deque ([' E ', ' d ', ' C ', ' B ', ' a '])  

Rotate (Put the right element on the left)

ImportCOLLECTIONSD=Collections.deque () d.extend (['a','b','C','D','e']) d.rotate (2)#specified number of times, default 1Print(d)#output: Deque ([' d ', ' e ', ' A ', ' B ', ' C ')

Python3 deque (bidirectional queue)