Lesson 82 - collections.ipynb

{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [],
   "source": [
    "from collections import Counter, deque\n",
    "import itertools\n",
    "import requests\n",
    "import re"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "# counter"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Counter({'red': 3, 'blue': 2, 'green': 1})"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "cnt = Counter()\n",
    "colours = [\"red\",\"blue\",\"green\",\"red\",\"red\",\"blue\"]\n",
    "for colour in colours:\n",
    "    cnt[colour] += 1\n",
    "cnt"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Counter({'red': 3, 'blue': 2, 'green': 1})"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "cnt = Counter(colours)\n",
    "cnt"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['the', 'boy', 'who', 'lived', 'mr', 'and', 'mrs', 'dursley', 'of', 'number']"
      ]
     },
     "execution_count": 5,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "with requests.get(\"https://raw.githubusercontent.com/formcept/whiteboard/master/nbviewer/notebooks/data/harrypotter/Book%201%20-%20The%20Philosopher's%20Stone.txt\") as book:\n",
    "    words = re.findall(r\"\\w+\",book.text.lower())\n",
    "words[:10]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [],
   "source": [
    "c = Counter(words)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[('the', 3975),\n",
       " ('and', 2271),\n",
       " ('to', 1860),\n",
       " ('he', 1757),\n",
       " ('a', 1687),\n",
       " ('harry', 1672),\n",
       " ('of', 1266),\n",
       " ('was', 1186),\n",
       " ('it', 1186),\n",
       " ('you', 1037)]"
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "c.most_common(10)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "(84445, 84445)"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "c.total(), len(words)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "0"
      ]
     },
     "execution_count": 9,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "c[\"paul\"]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "(Counter({'a': 4, 'b': 3, 'c': 2, 'd': 2, 'e': 2, 'f': 2, 'g': 1, 'h': 1}),\n",
       " Counter({'a': 1, 'b': 1, 'c': 1, 'd': 1, 'e': 1, 'f': 1, 'g': 1, 'h': 1}))"
      ]
     },
     "execution_count": 10,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "c1 = Counter(\"abcdefabcdefghaab\")\n",
    "c2 = Counter(\"abcdefgh\")\n",
    "c1, c2"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Counter({'a': 5, 'b': 4, 'c': 3, 'd': 3, 'e': 3, 'f': 3, 'g': 2, 'h': 2})"
      ]
     },
     "execution_count": 11,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "c1 + c2"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Counter({'a': 3, 'b': 2, 'c': 1, 'd': 1, 'e': 1, 'f': 1})"
      ]
     },
     "execution_count": 12,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "c1 - c2"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Counter({'a': 1, 'b': 1, 'c': 1, 'd': 1, 'e': 1, 'f': 1, 'g': 1, 'h': 1})"
      ]
     },
     "execution_count": 13,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "c1 & c2"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Counter({'a': 4, 'b': 3, 'c': 2, 'd': 2, 'e': 2, 'f': 2, 'g': 1, 'h': 1})"
      ]
     },
     "execution_count": 14,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "c1 | c2"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {},
   "outputs": [],
   "source": [
    "# deque"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "G\n",
      "H\n",
      "I\n"
     ]
    }
   ],
   "source": [
    "d = deque(\"ghi\")\n",
    "for letter in d:\n",
    "    print(letter.upper())"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "deque(['f', 'g', 'h', 'i', 'j'])"
      ]
     },
     "execution_count": 17,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "d.append(\"j\")\n",
    "d.appendleft(\"f\")\n",
    "d"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 18,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "deque(['g', 'h', 'i'])"
      ]
     },
     "execution_count": 18,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "d.pop()\n",
    "d.popleft()\n",
    "d"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "('g', 'i')"
      ]
     },
     "execution_count": 19,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "d[0],d[-1]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['g', 'h', 'i']"
      ]
     },
     "execution_count": 20,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "list(d)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['i', 'h', 'g']"
      ]
     },
     "execution_count": 21,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "list(reversed(d))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 22,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 22,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "'h' in d"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 23,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "deque(['g', 'h', 'i', 'j', 'k', 'l'])"
      ]
     },
     "execution_count": 23,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "d.extend(\"jkl\")\n",
    "d"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 24,
   "metadata": {},
   "outputs": [],
   "source": [
    "d.clear()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 25,
   "metadata": {},
   "outputs": [
    {
     "ename": "IndexError",
     "evalue": "pop from an empty deque",
     "output_type": "error",
     "traceback": [
      "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[1;31mIndexError\u001b[0m                                Traceback (most recent call last)",
      "\u001b[1;32mc:\\Users\\George Ogden\\OneDrive\\Desktop\\Understanding Python\\Lesson 82 - collections.ipynb Cell 25'\u001b[0m in \u001b[0;36m<cell line: 1>\u001b[1;34m()\u001b[0m\n\u001b[1;32m----> <a href='vscode-notebook-cell:/c%3A/Users/George%20Ogden/OneDrive/Desktop/Understanding%20Python/Lesson%2082%20-%20collections.ipynb#ch0000024?line=0'>1</a>\u001b[0m d\u001b[39m.\u001b[39;49mpop()\n",
      "\u001b[1;31mIndexError\u001b[0m: pop from an empty deque"
     ]
    }
   ],
   "source": [
    "d.pop()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 26,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "deque(['c', 'b', 'a'])"
      ]
     },
     "execution_count": 26,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "d.extendleft(\"abc\")\n",
    "d"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 27,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "deque(['b', 'a', 'c'])"
      ]
     },
     "execution_count": 27,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "d.rotate(-1)\n",
    "d"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 28,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "deque(['a', 'c', 'b'])"
      ]
     },
     "execution_count": 28,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "d.rotate(2)\n",
    "d"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 29,
   "metadata": {},
   "outputs": [],
   "source": [
    "def tail(url, n=20):\n",
    "    'Return the last n lines of a file'\n",
    "    with requests.get(url) as r:\n",
    "        return deque(r.text.splitlines(), n)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 30,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "deque(['',\n",
       "       '',\n",
       "       '',\n",
       "       'Page | 347 Harry Potter and the Philosophers Stone - J.K. Rowling ',\n",
       "       '',\n",
       "       '',\n",
       "       '',\n",
       "       '',\n",
       "       '“Oh, I will,” said Harry, and they were surprised at ',\n",
       "       'the grin that was spreading over his face. “ They don’t ',\n",
       "       'know we’re not allowed to use magic at home. I’m ',\n",
       "       'going to have a lot of fun with Dudley this summer...” ',\n",
       "       '',\n",
       "       '',\n",
       "       '',\n",
       "       'Page | 348 Harry Potter and the Philosophers Stone - J.K. Rowling ',\n",
       "       '',\n",
       "       '',\n",
       "       '',\n",
       "       ''])"
      ]
     },
     "execution_count": 30,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "tail(\"https://raw.githubusercontent.com/formcept/whiteboard/master/nbviewer/notebooks/data/harrypotter/Book%201%20-%20The%20Philosopher's%20Stone.txt\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 31,
   "metadata": {},
   "outputs": [],
   "source": [
    "def roundrobin(*iterables):\n",
    "    iterators = deque(map(iter, iterables))\n",
    "    while iterators:\n",
    "        try:\n",
    "            while True:\n",
    "                yield next(iterators[0])\n",
    "                iterators.rotate(-1)\n",
    "        except StopIteration:\n",
    "            # Remove an exhausted iterator.\n",
    "            iterators.popleft()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 32,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['A', 'D', 'E', 'B', 'F', 'C']"
      ]
     },
     "execution_count": 32,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "list(roundrobin('ABC', 'D', 'EF'))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 33,
   "metadata": {},
   "outputs": [],
   "source": [
    "def moving_average(iterable, n=3):\n",
    "    it = iter(iterable)\n",
    "    d = deque(itertools.islice(it, n-1))\n",
    "    d.appendleft(0)\n",
    "    s = sum(d)\n",
    "    for elem in it:\n",
    "        s += elem - d.popleft()\n",
    "        d.append(elem)\n",
    "        yield s / n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 34,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[40.0, 42.0, 45.0, 43.0]"
      ]
     },
     "execution_count": 34,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "list(moving_average([40, 30, 50, 46, 39, 44]))"
   ]
  }
 ],
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  "kernelspec": {
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