import collections # High-performance container datatypes
[docs]class Queue(object):
"""FIFO"""
def __init__(self):
self._queue = collections.deque()
[docs] def pull(self):
"""Remove and return the first element of the queue"""
try:
# Remove and return an element from the left side of the deque
element = self._queue.popleft()
except IndexError:
raise Exception('no elements are present')
return element
[docs] def put(self, element):
"""Appends the element as the last object of the queue"""
self._queue.append(element) # Add x to the right side of the deque
[docs] def is_empty(self):
return len(self._queue) == 0
[docs] def count(self):
return len(self._queue)
[docs] def clear(self):
"""Remove all elements of the queue"""
self._queue.clear()
[docs] def convert_to_list(self):
"""Return the elements in an ordered list"""
return list(self._queue)
def __str__(self):
line = ''
data_list = self.convert_to_list()
for item in data_list:
line += '%s\n' % str(item)
return line
# class Stack(Queue)
# override 'put' and 'pull' methods, and change deque's called methods