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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 2023<br>Instructor: Ron Mak</center>"
   ]
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   "metadata": {},
   "source": [
    "# 9.5 Serialization with JSON "
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### JSON Data Format "
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### The **JSON** (JavaScript Object Notation) data format is very commonly used by web applications and cloud-based services such as Twitter.\n",
    "#### A JSON object is similar to a Python dictionary. Each object contains a comma-separated list of _property names_ and _values_ surrounded by curly braces. For example:\n",
    "```\n",
    "{'account': 100, 'name': 'Jones', 'balance': 24.98}\n",
    "```\n",
    "#### JSON also has arrays, which look like Python lists. For example:\n",
    "```\n",
    "[100, 200, 300]\n",
    "```\n",
    "#### Values in JSON objects and arrays can be:\n",
    "- strings in _double_ quotes\n",
    "- numbers\n",
    "- Boolean values `true` and `false`\n",
    "- `null` (no value, like Python's `None`)\n",
    "- arrays\n",
    "- other (nested) JSON objects\n",
    "#### Python supports JSON through its Standard Library module `json`."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "accounts_dict = {'accounts': [ {'account': 100, 'name': 'Jones', 'balance':  24.98},\n",
    "                               {'account': 200, 'name': 'Doe',   'balance': 345.67}\n",
    "                             ]\n",
    "                }\n",
    "\n",
    "accounts_dict"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Serializing an Object to JSON\n",
    "#### We can **serialize** (convert to a stream of bytes) a dictionary object to a text file in JSON format with the `json` module's `dump()` function."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "import json\n",
    "\n",
    "with open('accounts.json', 'w') as accounts:\n",
    "    json.dump(accounts_dict, accounts)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Deserializing the JSON Text"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### Conversely, the `json` module's `load()` function reads a text file in JSON format and **deserializes** the data into a Python dictionary object."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "with open('accounts.json', 'r') as accounts:\n",
    "    accounts_json = json.load(accounts)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "accounts_json"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "accounts_json['accounts']"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "accounts_json['accounts'][0]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "accounts_json['accounts'][1]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Displaying the JSON Text"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### The `json` module's `dumps()` function (for \"dump string\") _pretty-prints_ (prints in a nice format) a JSON object."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "with open('accounts.json', 'r') as accounts:\n",
    "    print(json.dumps(json.load(accounts), indent=4))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "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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