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   "source": [
    "#### <center>San Jose State University<br>Department of Applied Data Science<br><br>**DATA 200<br>Computational Programming for Data Analytics**<br><br>Spring 2024<br>Instructor: Ron Mak</center>"
   ]
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   "source": [
    "## 6.2.1 Creating a Dictionary"
   ]
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   "source": [
    "#### So far, we've covered three built-in **sequence** collections: strings, lists, and tuples. Remember that sequences are ordered. Tonight: two **non-sequence** collections: **dictionaries** and **sets**.\n",
    "\n",
    "#### A dictionary is an **unordered** collection of **key-value pairs** that map immutable keys to values.\n",
    "\n",
    "#### A set is an **unordered** collection of **unique** immutable elements."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### Here is a dictionary of country codes. The keys are the country names, and the corresponding values are their internet country codes."
   ]
  },
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   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "country_codes = {'Finland': 'fi', 'South Africa': 'za', \n",
    "                  'Nepal': 'np'}\n",
    "                 "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "country_codes"
   ]
  },
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   "metadata": {},
   "source": [
    "#### When you display a dictionary, you get comma-separated key-value pairs all enclosed in a set of curly braces."
   ]
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   "metadata": {},
   "source": [
    "### Determining if a Dictionary Is Empty "
   ]
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   "metadata": {},
   "source": [
    "#### A non-empty dictionary evaluates to True."
   ]
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   "execution_count": null,
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   "outputs": [],
   "source": [
    "len(country_codes)"
   ]
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  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "if country_codes:\n",
    "    print('country_codes is not empty')\n",
    "else:\n",
    "    print('country_codes is empty')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### An empty dictionary evaluates to False."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "country_codes.clear()\n",
    "\n",
    "country_codes"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "if country_codes:\n",
    "    print('country_codes is not empty')\n",
    "else:\n",
    "    print('country_codes is empty')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
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   "outputs": [],
   "source": [
    "##########################################################################\n",
    "# (C) Copyright 2019 by Deitel & Associates, Inc. and                    #\n",
    "# Pearson Education, Inc. All Rights Reserved.                           #\n",
    "#                                                                        #\n",
    "# DISCLAIMER: The authors and publisher of this book have used their     #\n",
    "# best efforts in preparing the book. These efforts include the          #\n",
    "# development, research, and testing of the theories and programs        #\n",
    "# to determine their effectiveness. The authors and publisher make       #\n",
    "# no warranty of any kind, expressed or implied, with regard to these    #\n",
    "# programs or to the documentation contained in these books. The authors #\n",
    "# and publisher shall not be liable in any event for incidental or       #\n",
    "# consequential damages in connection with, or arising out of, the       #\n",
    "# furnishing, performance, or use of these programs.                     #\n",
    "##########################################################################\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Additional material (C) Copyright 2023 by Ronald Mak"
   ]
  }
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