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    "# Implementation of Queue\n",
    "\n",
    "In this lecture we will build on our previous understanding of Queues by implementing our own class of Queue!"
   ]
  },
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    "____\n",
    "## Queue Methods and Attributes\n",
    "\n",
    "\n",
    "Before we begin implementing our own queue, let's review the attribute and methods it will have:\n",
    "\n",
    "* Queue() creates a new queue that is empty. It needs no parameters and returns an empty queue.\n",
    "* enqueue(item) adds a new item to the rear of the queue. It needs the item and returns nothing.\n",
    "* dequeue() removes the front item from the queue. It needs no parameters and returns the item. The queue is modified.\n",
    "* isEmpty() tests to see whether the queue is empty. It needs no parameters and returns a boolean value.\n",
    "* size() returns the number of items in the queue. It needs no parameters and returns an integer."
   ]
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "____\n",
    "## Queue Implementation"
   ]
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  {
   "cell_type": "code",
   "execution_count": 1,
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   "source": [
    "class Queue:\n",
    "    def __init__(self):\n",
    "        self.items = []\n",
    "\n",
    "    def isEmpty(self):\n",
    "        return self.items == []\n",
    "\n",
    "    def enqueue(self, item):\n",
    "        self.items.insert(0,item)\n",
    "\n",
    "    def dequeue(self):\n",
    "        return self.items.pop()\n",
    "\n",
    "    def size(self):\n",
    "        return len(self.items)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": true
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   "outputs": [],
   "source": [
    "q = Queue()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "0"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "q.size()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "q.isEmpty()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "q.enqueue(1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "1"
      ]
     },
     "execution_count": 6,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "q.dequeue()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Good Job!"
   ]
  }
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