Queue ADT

Queue (ABC)

A queue is a First-In-First-Out ADT that supports insertion (enqueueing) of elements at one end and removal (dequeueing) of elements from the opposite end. The order in which elements are enqueued is maintained when dequeueing them.

__len__(self) special

Get the total number of elements stored in the queue

Returns:

Type	Description
int	count of elements in queue

Source code in queues/queue_custom.py

@abstractmethod
def __len__(self) -> int:
    """Get the total number of elements stored in the queue

    :returns: count of elements in queue
    """
    pass

dequeue(self)

Remove first element of the queue and return it

Returns:

Type	Description
Any	first element of queue

Source code in queues/queue_custom.py

@abstractmethod
def dequeue(self) -> Any:
    """Remove first element of the queue and return it

    :return: first element of queue
    """
    pass

enqueue(self, x)

Insert an element to the end of the queue

Parameters:

Name	Type	Description	Default
x	Any	element to add to the queue	required

Source code in queues/queue_custom.py

@abstractmethod
def enqueue(self, x: Any) -> None:
    """Insert an element to the end of the queue

    :param x: element to add to the queue
    """
    pass

get_first(self)

Return first element of the queue without removing it

Returns:

Type	Description
Any	first element of queue

Source code in queues/queue_custom.py

@abstractmethod
def get_first(self) -> Any:
    """Return first element of the queue without removing it

    :return: first element of queue
    """
    pass

is_empty(self)

Check if queue contains no elements

Returns:

Type	Description
bool	True if queue is empty, else False

Source code in queues/queue_custom.py

@abstractmethod
def is_empty(self) -> bool:
    """Check if queue contains no elements

    :return: True if queue is empty, else False
    """
    pass