{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### 5-3-6 先読みと後よみ"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "#<MatchData \"丁目10番地\" 1:\"10\">"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "#pattern = /(?<=丁目)(\\d+)(?=番地)/\n",
    "pattern = /(?:丁目)(\\d+)(?:番地)/\n",
    "\n",
    "pattern.match('神奈川県川崎市川崎区大宮町2丁目10番地')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "#<MatchData \"10\" 1:\"10\">"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "pattern = /(?<=丁目)(\\d+)(?=番地)/\n",
    "\n",
    "pattern.match('神奈川県川崎市川崎区大宮町2丁目10番地')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "#<MatchData \"10\" 1:\"10\">"
      ]
     },
     "execution_count": 5,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "pattern = /(?<=丁目)(\\d+)/\n",
    "\n",
    "pattern.match('神奈川県川崎市川崎区大宮町2丁目10番地')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "#<MatchData \"丁目10\" 1:\"10\">"
      ]
     },
     "execution_count": 10,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "pattern = /(?:丁目)(\\d+)/\n",
    "\n",
    "pattern.match('神奈川県川崎市川崎区大宮町2丁目10番地')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "nil\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "#<MatchData \"-01-01\" month_and_day:\"01-01\">"
      ]
     },
     "execution_count": 12,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "pattern = /(?<!2012)-(?<month_and_day>\\d{2}-\\d{2})/\n",
    "\n",
    "p pattern.match('2012-01-01')\n",
    "pattern.match('2016-01-01')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### 5-3-7 バックトラックの抑止"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\"ruby\"\n",
      "\"ruby3x3\"\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "\"ruby3x3\""
      ]
     },
     "execution_count": 13,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "pattern = /(\\w+)/\n",
    "\n",
    "p pattern.match('ruby')[1]\n",
    "p pattern.match('ruby3x3')[1]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "nil\n",
      "#<MatchData \"ruby5\" 1:\"ruby\">\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "#<MatchData \"ruby5\" 1:\"ruby\">"
      ]
     },
     "execution_count": 19,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "pattern = /(\\w+)[0-9]/\n",
    "\n",
    "p pattern.match('ruby')\n",
    "p pattern.match('ruby5')[1] # 本は => \"ruby5\" とあるが誤植"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "false"
      ]
     },
     "execution_count": 20,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "pattern = /(?>\\w+)[0-9]/\n",
    "\n",
    "pattern === 'ruby5'"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 23,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "true"
      ]
     },
     "execution_count": 23,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "pattern = /(?>\\w+)[0-9$]/\n",
    "\n",
    "pattern === 'ruby3$3'"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### 5-3-8 オプションの指定"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 24,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "/ruby/mi"
      ]
     },
     "execution_count": 24,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "/ruby/mi\n",
    "\n",
    "%r(ruby)mi"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 25,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[/foo/, /bar/]\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "[/foo/, /foo/]"
      ]
     },
     "execution_count": 25,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "p %w(foo bar).map { |str|  /#{str}/}\n",
    "%w(foo bar).map { |str|  /#{str}/o}"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 26,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "false\n",
      "true\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "true"
      ]
     },
     "execution_count": 26,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "r = /R(?i)uby(?-i)/ # i オプションは -iがくるまでずっと有効\n",
    "\n",
    "p r === 'ruby'\n",
    "p r === 'Ruby'\n",
    "r === 'RUBY'"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "次回は \"5-4 Comparable\"から"
   ]
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Ruby 2.2.2",
   "language": "ruby",
   "name": "ruby"
  },
  "language_info": {
   "file_extension": "rb",
   "mimetype": "application/x-ruby",
   "name": "ruby",
   "version": "2.2.2"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 1
}