{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 5-7 IO/File\n",
    "### 5-7-1 File/IO オブジェクトの操作"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "hoge\n",
      "\n"
     ]
    }
   ],
   "source": [
    "file = File.open('fname.txt')\n",
    "puts file.read\n",
    "file.close"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "hoge\n",
      "\n"
     ]
    }
   ],
   "source": [
    "File.open 'fname.txt' do |file|\n",
    "  puts file.read\n",
    "end"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\"hoge\\n\"\n",
      "\"fuga\\n\"\n",
      "\"hey\\n\"\n",
      "\"ho\\n\"\n"
     ]
    }
   ],
   "source": [
    "File.open 'fname.txt' do |file|\n",
    "  while line = file.gets\n",
    "    p line\n",
    "  end\n",
    "end"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\"hoge\\n\"\n",
      "\"fuga\\n\"\n",
      "\"hey\\n\"\n",
      "\"ho\\n\"\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "hoge\n",
       "fuga\n",
       "hey\n",
       "ho\n"
      ]
     },
     "execution_count": 13,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "File.open 'fname.txt' do |file|\n",
    "  file.each_line do |line|\n",
    "    p line\n",
    "  end\n",
    "end"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "104\n",
      "111\n",
      "103\n",
      "101\n",
      "10\n",
      "102\n",
      "117\n",
      "103\n",
      "97\n",
      "10\n",
      "104\n",
      "101\n",
      "121\n",
      "10\n",
      "104\n",
      "111\n",
      "10\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "hoge\n",
       "fuga\n",
       "hey\n",
       "ho\n"
      ]
     },
     "execution_count": 15,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "File.open 'fname.txt' do |file|\n",
    "  file.each_byte do |line|\n",
    "    p line\n",
    "  end\n",
    "end"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "\"hoge\\nfuga\\nhey\\nho\\n\""
      ]
     },
     "execution_count": 16,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "File.read('fname.txt')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 18,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "5"
      ]
     },
     "execution_count": 18,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "File.open 'fname2.txt', 'w' do |f|\n",
    "  f.write 'Hello'\n",
    "end"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "\"Hello\""
      ]
     },
     "execution_count": 19,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "File.read('fname2.txt')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "97"
      ]
     },
     "execution_count": 20,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "File.open 'foo', File::WRONLY | File::CREAT do |f|\n",
    " # \"puts¥n\" と書き込み\n",
    " f.puts 'puts'\n",
    " # 改行文字（¥n）だけを書き込み\n",
    " f.puts\n",
    " # \"print\" と書き込み\n",
    " f.print 'print'\n",
    " # \"007\" と書き込み\n",
    " f.printf \"%03d\", 7\n",
    " # \"a\" と書き込み\n",
    " f.putc 97\n",
    "end"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "\"puts\\n\\nprint007a\""
      ]
     },
     "execution_count": 21,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "File.read('foo')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "■アクセス位置の操作"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 22,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "hoge\n",
      "fuga\n",
      "hey\n",
      "ho\n",
      "文字列を追記\n",
      "\n"
     ]
    }
   ],
   "source": [
    "File.open 'fname.txt', 'a+' do |f|\n",
    "  f.puts '文字列を追記'\n",
    "  f.rewind\n",
    "  puts f.read\n",
    "end"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 23,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\n"
     ]
    }
   ],
   "source": [
    "File.open 'fname.txt', 'a+' do |f|\n",
    "  f.puts '文字列を追記2回目'\n",
    "  #f.rewind\n",
    "  puts f.read\n",
    "end"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 24,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "0"
      ]
     },
     "execution_count": 24,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "File.open 'fname.txt' do |f|\n",
    "  f.seek 10\n",
    "  f.seek -10, IO::SEEK_CUR\n",
    "  f.seek -10, IO::SEEK_END\n",
    "end"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 25,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "30\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "30"
      ]
     },
     "execution_count": 25,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "File.open 'fname.txt' do |f|\n",
    "  f.pos = 30\n",
    "  p f.pos\n",
    "end"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 26,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "30\n",
      "\"を追記\\n文字列を追記2回目\\n\"\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "\"を追記\\n文字列を追記2回目\\n\""
      ]
     },
     "execution_count": 26,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "File.open 'fname.txt' do |f|\n",
    "  f.pos = 30\n",
    "  p f.pos\n",
    "  p f.read\n",
    "end"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "■エンコーディングの扱い"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 28,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\"こんにちは\\n\"\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "\"こんにちは\\n\""
      ]
     },
     "execution_count": 28,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "File.open 'utf16.txt' do |f|\n",
    "  f.set_encoding('UTF-8')\n",
    "  f.set_encoding('UTF-16LE', 'UTF-8')\n",
    "  f.set_encoding('UTF-16LE:UTF-8')\n",
    "  p f.read\n",
    "end"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 29,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "#<Encoding:UTF-8>"
      ]
     },
     "execution_count": 29,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "Encoding.default_external"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 30,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "EUC-JP\n",
      "UTF-8\n"
     ]
    }
   ],
   "source": [
    "File.open 'fname.txt', 'r:euc-jp:utf-8' do |f|\n",
    "  puts f.external_encoding\n",
    "  puts f.internal_encoding\n",
    "end"
   ]
  }
 ],
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   "name": "ruby"
  },
  "language_info": {
   "file_extension": ".rb",
   "mimetype": "application/x-ruby",
   "name": "ruby",
   "version": "2.4.1"
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