{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "## 通常のリスト生成 \n",
    "(リスト外延表記: list  extension)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": false,
    "scrolled": true
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]"
      ]
     },
     "execution_count": 1,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "extension_1 = []\n",
    "for i in range(10):\n",
    "    extension_1.append(i)\n",
    "extension_1"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "## リスト内包表記\n",
    "list comprehension"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "基本構文  \n",
    "[ **element** for **element** in **iterator**]  \n",
    "僕は先に`[i for i in]`だけ書いてから修飾することが多いです。 "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": false,
    "scrolled": true
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]"
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "comprehension_1= [i for i in range(10)]\n",
    "comprehension_1"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "## 速度"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "100 loops, best of 3: 3.37 ms per loop\n"
     ]
    }
   ],
   "source": [
    "%%timeit\n",
    "extension_1 = []\n",
    "for i in range(10000):\n",
    "    extension_1.append(i)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "1000 loops, best of 3: 1.05 ms per loop\n"
     ]
    }
   ],
   "source": [
    "%%timeit\n",
    "comprehension_1= [i for i in range(10000)]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "source": [
    "list内包表記はコードがすっきりするだけでなく速度面でも有利です  \n",
    "[参考: Pythonの内包表記はなぜ速い？](http://dsas.blog.klab.org/archives/51742727.html)  \n",
    "遅い理由は大きく２つ\n",
    "- ループする度にリストオブジェクトのappendを参照する\n",
    "- appendをpythonの関数として実行する\n",
    "\n",
    "前者の影響はループの外に参照を追い出すことでも解消できます"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "1000 loops, best of 3: 1.57 ms per loop\n"
     ]
    }
   ],
   "source": [
    "%%timeit\n",
    "extension_1_ = []\n",
    "append=extension_1_.append\n",
    "for i in range(10000):\n",
    "    append(i)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "## ifを含む場合(後置if)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "リスト内包表記は後置ifが使えます"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[0, 2, 4, 6, 8]"
      ]
     },
     "execution_count": 6,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "extension_2 =[]\n",
    "for i in range(10):\n",
    "    if i%2==0:\n",
    "        extension_2.append(i)\n",
    "extension_2"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[0, 2, 4, 6, 8]"
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "comprehension_2 = [i for i in range(10) if i%2==0]\n",
    "comprehension_2"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {
    "collapsed": false,
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "100 loops, best of 3: 4.08 ms per loop\n"
     ]
    }
   ],
   "source": [
    "%%timeit\n",
    "extension_2 =[]\n",
    "for i in range(10000):\n",
    "    if i%2==0:\n",
    "        extension_2.append(i)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "100 loops, best of 3: 3.15 ms per loop\n"
     ]
    }
   ],
   "source": [
    "%%timeit\n",
    "comprehension_2 = [i for i in range(10000) if i%2==0]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "100 loops, best of 3: 3.81 ms per loop\n"
     ]
    }
   ],
   "source": [
    "%%timeit\n",
    "extension_2_ =[]\n",
    "append=extension_2_.append\n",
    "for i in range(10000):\n",
    "    if i%2==0:\n",
    "        append(i)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "実はifが計算律速になるので、無理にリスト内包表記にする必要がなかったりします。"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "## if ~ elseを含む場合 (条件演算子)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "紛らわしいですが、else節を含む場合は条件演算子（他で言う三項演算子）を使うのでifの位置が変わります  \n",
    "（条件演算子はpython 2.5以降のみ対応です）"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[0, '1', 2, '3', 4, '5', 6, '7', 8, '9']"
      ]
     },
     "execution_count": 11,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "extension_3 =[]\n",
    "for i in range(10):\n",
    "    if i%2==0:\n",
    "        extension_3.append(i)\n",
    "    else:\n",
    "        extension_3.append(str(i))\n",
    "extension_3"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[0, '1', 2, '3', 4, '5', 6, '7', 8, '9']"
      ]
     },
     "execution_count": 12,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "comprehension_3 = [ i if i%2==0 else str(i) for i in range(10)]\n",
    "comprehension_3"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "実際にはこちらと等価だと思えば理解しやすいかもしれません"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[0, '1', 2, '3', 4, '5', 6, '7', 8, '9']"
      ]
     },
     "execution_count": 13,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "extension_3_conditional =[]\n",
    "for i in range(10):\n",
    "    extension_3_conditional.append(i) if i%2==0 else extension_3_conditional.append(str(i))\n",
    "extension_3_conditional"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "source": [
    "一応速度を測ってみます"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {
    "collapsed": false,
    "slideshow": {
     "slide_type": "-"
    }
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "100 loops, best of 3: 12.4 ms per loop\n"
     ]
    }
   ],
   "source": [
    "%%timeit\n",
    "extension_3 =[]\n",
    "for i in range(10000):\n",
    "    if i%2==0:\n",
    "        extension_3.append(i)\n",
    "    else:\n",
    "        extension_3.append(str(i))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "100 loops, best of 3: 10.3 ms per loop\n"
     ]
    }
   ],
   "source": [
    "%%timeit\n",
    "extension_3_ =[]\n",
    "append=extension_3_.append\n",
    "for i in range(10000):\n",
    "    if i%2==0:\n",
    "        append(i)\n",
    "    else:\n",
    "        append(str(i))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {
    "collapsed": false,
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "100 loops, best of 3: 9.04 ms per loop\n"
     ]
    }
   ],
   "source": [
    "%%timeit\n",
    "extension_3_conditional_ =[]\n",
    "append=extension_3_conditional_.append\n",
    "for i in range(10000):\n",
    "    append(i) if i%2==0 else append(str(i))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {
    "collapsed": false,
    "scrolled": true
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "100 loops, best of 3: 8.6 ms per loop\n"
     ]
    }
   ],
   "source": [
    "%%timeit\n",
    "comprehension_3 = [ i if i%2==0 else str(i) for i in range(10000)]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "あまり内包表記による高速化はありません"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "## 辞書内包表記とセット内包表記"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "python2.7以降ではリスト以外の内包表記として、辞書内包やセット内包も使えます。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 18,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "{'7': 7, '8': 8, '2': 2, '9': 9, '0': 0, '1': 1, '6': 6, '5': 5, '4': 4, '3': 3}\n"
     ]
    }
   ],
   "source": [
    "comprehension_dict = {str(i):i for i in range(10)}\n",
    "print(comprehension_dict)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "zipとかと相性いいです。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "{'kinoko': 'yama', 'suginoko': 'mura', 'takenoko': 'sato'}"
      ]
     },
     "execution_count": 19,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "label = [\"kinoko\", \"takenoko\", \"suginoko\"]\n",
    "feature = [\"yama\", \"sato\", \"mura\"]\n",
    "{i:j for i,j in zip(label,feature)}"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "source": [
    "python2.6まではdictにtupleを渡してあげます。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "{'7': 7, '8': 8, '2': 2, '9': 9, '0': 0, '1': 1, '6': 6, '5': 5, '4': 4, '3': 3}\n"
     ]
    }
   ],
   "source": [
    "comprehension_dict2 = dict((str(i),i) for i in range(10))\n",
    "print(comprehension_dict2)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "後置ifも使えます。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "{'8': 8, '6': 6, '2': 2, '4': 4, '0': 0}\n"
     ]
    }
   ],
   "source": [
    "comprehension_dict2 = {str(i):i for i in range(10) if i%2==0}\n",
    "print(comprehension_dict2)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "条件演算子も使えます。  \n",
    "条件演算子なので、「:」の前後のkeyとvalueそれぞれに記載する必要があります。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 22,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "{'2': 2, 1: '1', 3: '3', 5: '5', '0': 0, 7: '7', 9: '9', '6': 6, '4': 4, '8': 8}\n"
     ]
    }
   ],
   "source": [
    "comprehension_dict3 = {str(i) if i%2==0 else i : i if i%2==0 else str(i) for i in range(10)}\n",
    "print(comprehension_dict3)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "これは動かないです。(以前やりましたorz)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 23,
   "metadata": {
    "collapsed": false,
    "scrolled": true
   },
   "outputs": [
    {
     "ename": "SyntaxError",
     "evalue": "invalid syntax (<ipython-input-23-60c72c76aa53>, line 1)",
     "output_type": "error",
     "traceback": [
      "\u001b[1;36m  File \u001b[1;32m\"<ipython-input-23-60c72c76aa53>\"\u001b[1;36m, line \u001b[1;32m1\u001b[0m\n\u001b[1;33m    comprehension_dict4 = {str(i):i if i%2==0 else i:str(i) for i in range(10)}\u001b[0m\n\u001b[1;37m                                                    ^\u001b[0m\n\u001b[1;31mSyntaxError\u001b[0m\u001b[1;31m:\u001b[0m invalid syntax\n"
     ]
    }
   ],
   "source": [
    "comprehension_dict4 = {str(i):i if i%2==0 else i:str(i) for i in range(10)}"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "セット内包表記にしたい時は : なしで {} で囲みます。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 24,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "{0, 1, 2, 3, 4}"
      ]
     },
     "execution_count": 24,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "comprehension_set={i%5 for i in range(10)}\n",
    "comprehension_set"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "## ジェネレータ式とタプル内包表記"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "構文から勘違いしやすいですが、()で囲んでもタプル内包表記になりません。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 25,
   "metadata": {
    "collapsed": false,
    "scrolled": true
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "<generator object <genexpr> at 0x7f3000219678>"
      ]
     },
     "execution_count": 25,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "comprehension_gen=(i%5 for i in range(10))\n",
    "comprehension_gen"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 27,
   "metadata": {
    "collapsed": false,
    "scrolled": true,
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0\n",
      "1\n",
      "2\n",
      "3\n",
      "4\n",
      "0\n",
      "1\n",
      "2\n",
      "3\n",
      "4\n"
     ]
    }
   ],
   "source": [
    "for i in comprehension_gen:print(i)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "（）で囲うとジェネレータが発生します。むしろタプル内包表記より使います。  \n",
    "リストと違ってメモリ中に全要素を格納しないで、次の要素を順番に生成します。    \n",
    "内包表記を使わない書き方は下記ですが、一旦　ジェネレータを生成する関数を作らないと行けないので面倒です。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 28,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "<generator object gen_func at 0x7f3000166830>"
      ]
     },
     "execution_count": 28,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "def gen_func():\n",
    "    for i in range(10):\n",
    "        yield i\n",
    "extension_gen = gen_func()\n",
    "extension_gen"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "タプル内包表記が必要なことはあまりないですが、もしどうしても必要ならリスト内包表記をtuple関数に渡すしかないです。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 29,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "(0, 1, 2, 3, 4, 5, 6, 7, 8, 9)"
      ]
     },
     "execution_count": 29,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "tuple([i for i in range(10)])"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "## 闇への道"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "この節を読み終えた後は[リーダブルコード](http://www.amazon.co.jp/dp/4873115655)を読んで浄化されることを推奨します。"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "#### 条件演算子を複数つなげる"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 30,
   "metadata": {
    "collapsed": false,
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "1\n",
      "2\n",
      "fizz\n",
      "4\n",
      "buzz\n",
      "fizz\n",
      "7\n",
      "8\n",
      "fizz\n",
      "buzz\n",
      "11\n",
      "fizz\n",
      "13\n",
      "14\n",
      "fizzbuzz\n"
     ]
    }
   ],
   "source": [
    "for i in range(1,16):\n",
    "    if i%15==0:\n",
    "        print (\"fizzbuzz\")\n",
    "    elif i%3==0:\n",
    "        print (\"fizz\")\n",
    "    elif i%5==0:\n",
    "        print (\"buzz\")\n",
    "    else:\n",
    "        print(i)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 31,
   "metadata": {
    "collapsed": false,
    "scrolled": false,
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[1,\n",
       " 2,\n",
       " 'fizz',\n",
       " 4,\n",
       " 'buzz',\n",
       " 'fizz',\n",
       " 7,\n",
       " 8,\n",
       " 'fizz',\n",
       " 'buzz',\n",
       " 11,\n",
       " 'fizz',\n",
       " 13,\n",
       " 14,\n",
       " 'fizzbuzz']"
      ]
     },
     "execution_count": 31,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "[\"fizzbuzz\" if i%15==0 else \"fizz\" if i%3==0 else \"buzz\"\n",
    " if i%5==0 else i for i in range(1,16)]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "ネスト(多重配列)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 32,
   "metadata": {
    "collapsed": false,
    "scrolled": true
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[[0, 1, 2, 3, 4, 5, 6, 7, 8, 9],\n",
       " [0, 1, 2, 3, 4, 5, 6, 7, 8, 9],\n",
       " [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]]"
      ]
     },
     "execution_count": 32,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "outer_list=[]\n",
    "for i in range(3):\n",
    "    innter_list=[]\n",
    "    for j in range(10):\n",
    "        innter_list.append(j)\n",
    "    outer_list.append(innter_list)\n",
    "outer_list"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 33,
   "metadata": {
    "collapsed": false,
    "scrolled": true
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[[0, 1, 2, 3, 4, 5, 6, 7, 8, 9],\n",
       " [0, 1, 2, 3, 4, 5, 6, 7, 8, 9],\n",
       " [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]]"
      ]
     },
     "execution_count": 33,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "[[j for j in range(10)] for i in range(3)]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "フラッタン  \n",
    "この辺から可読性著しく悪くなります。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 34,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "init=[[1,2,3],[4,5],[6,7]]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 35,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[1, 2, 3, 4, 5, 6, 7]"
      ]
     },
     "execution_count": 35,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "flatten=[]\n",
    "for outer in init:\n",
    "    for inner in outer:\n",
    "        flatten.append(inner)\n",
    "flatten"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "これと等価"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 36,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[1, 2, 3, 4, 5, 6, 7]"
      ]
     },
     "execution_count": 36,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "[inner for outer in init for inner in outer]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "基本的には左側のfor節から順番に読んでいって、最後にリストに入れるものが頭にくる  \n",
    "インデントするならこんな感じ"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 37,
   "metadata": {
    "collapsed": false,
    "scrolled": true
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[1, 2, 3, 4, 5, 6, 7]"
      ]
     },
     "execution_count": 37,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "[\n",
    "inner\n",
    "for outer in init\n",
    "    for inner in outer\n",
    "]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "パタトクカシー"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 38,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'パタトクカシーー'"
      ]
     },
     "execution_count": 38,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "pato=\"パトカー\"\n",
    "taxi=\"タクシー\"\n",
    "rslt=[]\n",
    "for i in zip(pato,taxi):\n",
    "    for j in i:\n",
    "        rslt.append(\"\".join(j))\n",
    "\"\".join(rslt)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 39,
   "metadata": {
    "collapsed": false,
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'パタトクカシーー'"
      ]
     },
     "execution_count": 39,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "\"\".join([\"\".join(j) for i in zip(pato,taxi) for j in i])"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "インデントすると"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 40,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'パタトクカシーー'"
      ]
     },
     "execution_count": 40,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "\"\".join(\n",
    "  [\"\".join(j)\n",
    "    for i in zip(pato,taxi)\n",
    "      for j in i\n",
    "  ]\n",
    ")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "source": [
    "printとか入れてもできる"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 41,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "パ\n",
      "タ\n",
      "ト\n",
      "ク\n",
      "カ\n",
      "シ\n",
      "ー\n",
      "ー\n"
     ]
    }
   ],
   "source": [
    "for i in zip(pato,taxi):\n",
    "    for j in i:\n",
    "        for k in j: print(k)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 42,
   "metadata": {
    "collapsed": false,
    "scrolled": true
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "パ\n",
      "タ\n",
      "ト\n",
      "ク\n",
      "カ\n",
      "シ\n",
      "ー\n",
      "ー\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "[None, None, None, None, None, None, None, None]"
      ]
     },
     "execution_count": 42,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "[print(k) for i in zip(pato,taxi) for j in i for k in j]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "if 節との多重ループの合わせ技"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 43,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "import re\n",
    "DIO=[\"U\",\"無駄\",\"RR\",\"貧弱ゥ\",\"Y\"]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 44,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'UURRRRYY'"
      ]
     },
     "execution_count": 44,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "rslt=[]\n",
    "for i in DIO:\n",
    "    if re.match(\"[URY]+\",i):\n",
    "        for j in i:\n",
    "            rslt.append(j*2)\n",
    "\"\".join(rslt)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 45,
   "metadata": {
    "collapsed": false,
    "slideshow": {
     "slide_type": "-"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'UUURRRRRRYYY'"
      ]
     },
     "execution_count": 45,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "\"\".join([j*3 for i in DIO if re.match(\"[URY]+\",i) for j in i])"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "インデントするとこんな感じ"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 46,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'UUUURRRRRRRRYYYY'"
      ]
     },
     "execution_count": 46,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "\"\".join(\n",
    "  [\n",
    "    j*4\n",
    "      for i in DIO\n",
    "        if re.match(\"[URY]+\",i)\n",
    "          for j in i\n",
    "    ]\n",
    ")"
   ]
  }
 ],
 "metadata": {
  "celltoolbar": "Slideshow",
  "kernelspec": {
   "display_name": "Python 3",
   "language": "python",
   "name": "python3"
  },
  "language_info": {
   "codemirror_mode": {
    "name": "ipython",
    "version": 3
   },
   "file_extension": ".py",
   "mimetype": "text/x-python",
   "name": "python",
   "nbconvert_exporter": "python",
   "pygments_lexer": "ipython3",
   "version": "3.5.1"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 0
}