{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Reading and Writing files"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Lorem ipsum dolor sit amet, consectetur adipiscing elit. \n",
      "\n",
      "Suspendisse vel risus a felis consectetur aliquet non ut mi. \n",
      "\n",
      "Quisque a posuere lorem.\n",
      "\n",
      "Curabitur nec arcu ligula.\n",
      "\n"
     ]
    }
   ],
   "source": [
    "f = open(\"file-demo-read.txt\", \"r\")\n",
    "data = f.read()\n",
    "print(data)\n",
    "f.close()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# More clean way. The close method will be implicitly called just before exiting with block."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Lorem ipsum dolor sit amet, consectetur adipiscing elit. \n",
      "\n",
      "Suspendisse vel risus a felis consectetur aliquet non ut mi. \n",
      "\n",
      "Quisque a posuere lorem.\n",
      "\n",
      "Curabitur nec arcu ligula.\n",
      "\n"
     ]
    }
   ],
   "source": [
    "with open(\"file-demo-read.txt\", \"r\") as f:\n",
    "    data = f.read()\n",
    "\n",
    "print(data)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Reading one line at a time"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Lorem ipsum dolor sit amet, consectetur adipiscing elit. \n",
      "\n"
     ]
    }
   ],
   "source": [
    "with open(\"file-demo-read.txt\", \"r\") as f:\n",
    "    data = f.readline()\n",
    "\n",
    "print(data)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Writing into file"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [],
   "source": [
    "f = open(\"file-demo-write.txt\", \"r+\")\n",
    "f.write(\"This is a sample text.\")\n",
    "f.close()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Reading the written content"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "This is a sample text.\n"
     ]
    }
   ],
   "source": [
    "f = open(\"file-demo-write.txt\", \"r\")\n",
    "data = f.read()\n",
    "print(data)\n",
    "f.close()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# File positioning"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "is a sample text.\n",
      "This is a sample text.\n"
     ]
    }
   ],
   "source": [
    "f = open(\"file-demo-write.txt\", \"r\")\n",
    "f.seek(5)\n",
    "data = f.readline()\n",
    "print(data)\n",
    "f.seek(0)\n",
    "data = f.readline()\n",
    "print(data)\n",
    "f.close()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# File system operations"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [],
   "source": [
    "import os"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Create a directory"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [],
   "source": [
    "os.mkdir(\"demo\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Rename a directory"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [],
   "source": [
    "os.rename(\"demo\", \"demo-dir\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Change current working directory"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [],
   "source": [
    "curr_dir_backup = os.getcwd()\n",
    "os.chdir(\"demo-dir\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Print current working directory"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "/home/jovyan/demo-dir\n"
     ]
    }
   ],
   "source": [
    "curr_dir = os.getcwd()\n",
    "print(curr_dir)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Create a file under this directory"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {},
   "outputs": [],
   "source": [
    "f= open(\"demo.txt\",\"w+\")\n",
    "f.close()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Rename this file"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {},
   "outputs": [],
   "source": [
    "os.rename(\"demo.txt\", \"demo-file.txt\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Create two directory under this directory"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {},
   "outputs": [],
   "source": [
    "os.mkdir(\"demo-sub-dir-1\")\n",
    "os.mkdir(\"demo-sub-dir-2\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### List all files and directories"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['demo-sub-dir-2', 'demo-file.txt', 'demo-sub-dir-1']\n"
     ]
    }
   ],
   "source": [
    "dir_list = os.listdir()\n",
    "print(dir_list)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Get the statistics of a director. Current directory in the case below."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "os.stat_result(st_mode=16877, st_ino=22774768, st_dev=1048804, st_nlink=4, st_uid=1000, st_gid=1000, st_size=4096, st_atime=1538149930, st_mtime=1538149928, st_ctime=1538149928)\n"
     ]
    }
   ],
   "source": [
    "stat = os.stat(\".\")\n",
    "print(stat)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Clean up"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {},
   "outputs": [],
   "source": [
    "if(os.path.exists(\"../demo-dir\")):\n",
    "    if(os.path.exists(\"demo-sub-dir-1\")):\n",
    "        os.rmdir(\"demo-sub-dir-1\")\n",
    "    if(os.path.exists(\"demo-sub-dir-2\")):\n",
    "        os.rmdir(\"demo-sub-dir-2\")\n",
    "    if(os.path.isfile(\"demo-file.txt\")):\n",
    "        os.remove(\"demo-file.txt\")\n",
    "    os.rmdir(\"../demo-dir\")\n",
    "os.chdir(curr_dir_backup)"
   ]
  }
 ],
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  "kernelspec": {
   "display_name": "Python 3",
   "language": "python",
   "name": "python3"
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  "language_info": {
   "codemirror_mode": {
    "name": "ipython",
    "version": 3
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   "file_extension": ".py",
   "mimetype": "text/x-python",
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   "pygments_lexer": "ipython3",
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