Tutorial by Examples: deque

The main methods that are useful with this class are popleft and appendleft from collections import deque d = deque([1, 2, 3]) p = d.popleft() # p = 1, d = deque([2, 3]) d.appendleft(5) # d = deque([5, 2, 3])

Use the maxlen parameter while creating a deque to limit the size of the deque: from collections import deque d = deque(maxlen=3) # only holds 3 items d.append(1) # deque([1]) d.append(2) # deque([1, 2]) d.append(3) # deque([1, 2, 3]) d.append(4) # deque([2, 3, 4]) (1 is removed because i...

Creating empty deque: dl = deque() # deque([]) creating empty deque Creating deque with some elements: dl = deque([1, 2, 3, 4]) # deque([1, 2, 3, 4]) Adding element to deque: dl.append(5) # deque([1, 2, 3, 4, 5]) Adding element left side of deque: dl.appendleft(0) # deque([0, 1, 2, ...

A Deque is a "double ended queue" which means that a elements can be added at the front or the tail of the queue. The queue only can add elements to the tail of a queue. The Deque inherits the Queue interface which means the regular methods remain, however the Deque interface offers addit...

$scheme = 'https' $url_format = '{0}://example.vertigion.com/foos?{1}' $qs_data = @{ 'foo1'='bar1'; 'foo2'= 'complex;/?:@&=+$, bar''"'; 'complex;/?:@&=+$, foo''"'='bar2'; } [System.Collections.ArrayList] $qs_array = @() foreach ($qs in $qs_data.GetEnumerator()...

$scheme = 'https' $url_format = '{0}://example.vertigion.com/foos?{1}' $qs_data = @{ 'foo1'='bar1'; 'foo2'= 'complex;/?:@&=+$, bar''"'; 'complex;/?:@&=+$, foo''"'='bar2'; } [System.Collections.ArrayList] $qs_array = @() foreach ($qs in $qs_data.GetEnumerator()...

Returns a new deque object initialized left-to-right (using append()) with data from iterable. If iterable is not specified, the new deque is empty. Deques are a generalization of stacks and queues (the name is pronounced “deck” and is short for “double-ended queue”). Deques support thread-safe, me...

A deque is a double-ended queue. class Deque: def __init__(self): self.items = [] def isEmpty(self): return self.items == [] def addFront(self, item): self.items.append(item) def addRear(self, item): self.items.insert(0,item) def removeFront(self): return self....

Deque deque = new LinkedList(); //Adding element at tail deque.add("Item1"); //Adding element at head deque.addFirst("Item2"); //Adding element at tail deque.addLast("Item3");

//Retrieves and removes the head of the queue represented by this deque Object headItem = deque.remove(); //Retrieves and removes the first element of this deque. Object firstItem = deque.removeFirst(); //Retrieves and removes the last element of this deque. Object lastItem = deque.removeLa...

//Using Iterator Iterator iterator = deque.iterator(); while(iterator.hasNext(){ String Item = (String) iterator.next(); } //Using For Loop for(Object object : deque) { String Item = (String) object; }