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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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   "metadata": {},
   "source": [
    "# 2.2 Variables and Assignment Statements"
   ]
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   "metadata": {},
   "source": [
    "#### We can use IPython’s interactive mode, and we can also use a Jupyter notebook."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "45 + 72"
   ]
  },
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   "metadata": {},
   "source": [
    "#### **Identifiers** are names that you use in a Python program. **Variables** are identifiers that represent values  at runtime (when the code is executing).\n",
    "\n",
    "#### An **assignment statement** sets the value of a variable at runtime."
   ]
  },
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   "cell_type": "code",
   "execution_count": null,
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   "outputs": [],
   "source": [
    "x = 7"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "y = 3"
   ]
  },
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Adding Variable Values and Viewing the Result"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "x + y"
   ]
  },
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Calculations in Assignment Statements"
   ]
  },
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   "cell_type": "code",
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   "outputs": [],
   "source": [
    "total = x + y"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "total"
   ]
  },
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   "metadata": {},
   "source": [
    "#### **EXERCISE:** Calculate the sum of `10.8`, `12.2` and `0.2`, store it in the variable `total`, then display `total`’s value."
   ]
  },
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   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "total = 10.8 + 12.2 + 0.2\n",
    "total"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Python Style"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### The **_Python Style Guide_** recommends using a space around the equal sign."
   ]
  },
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Variable Names"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### A Python identifier may consist of letters, digits, and underscore ( _ ) characters, but it cannot begin with a digit. Identifiers are case sensitive: `count` and `Count` are two different identifiers"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### We can also use the underscore to break up writing large numbers. For example, the integer value 53,182: `53_182`"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "53182"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "53_182"
   ]
  },
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Types"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### Every value has a **datatype**. A scalar value is a single value, such as a numeric value.\n",
    "- Use the `type()` function to determine a value’s type."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "type(x)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "type(10.5)"
   ]
  },
  {
   "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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