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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": [
    "# Object-Oriented Programming"
   ]
  },
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   "source": [
    "## 10.2.1 Test-Driving Class `Account` \n",
    "#### Object-oriented programming (OOP) is the programming paradigm of many modern languages such as Java, C++, and Python."
   ]
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    "### Datatype\n",
    "#### Recall that a **datatype** is an attribute of a value. It determines:\n",
    "- #### What it can be (integer, float, or decimal number, string, list, numpy array, etc.)\n",
    "- #### What operations it can work on it (addition, concatenation, substring, etc.)\n",
    "- #### How it is printed or displayed, or how it can be formatted."
   ]
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    "### Objects\n",
    "#### We've used values that are **objects**, such as strings.\n",
    "#### Objects have special functions called **methods** that we can call on the object. To make a method call on an object value, follow the value (which can be in a variable) with a dot followed by the method name. The method call can have arguments. For example, if variable `str` has a string value:\n",
    "- #### `str.strip()` returns a new string without leading and trailing whitespace.\n",
    "- #### `str.count('to', 14)` returns the number of times `to` is in the string starting at index position 14."
   ]
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   "source": [
    "### Classes\n",
    "#### Like other OOP languages, Python allows us to create a custom datatype by defining a **classs**. A class is model or blueprint for creating new values of the class datatype during run time. These values are objects. We **instantiate** an object when we create the object from its class."
   ]
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   "source": [
    "### Every value is an object\n",
    "#### In Python, **every** value is an object. Of course, a string is an object, but so is an integer or a float number. Therefore, Python comes with many built-in, predefined classes, such as `string`, `int`, and `float`. Each class's objects has methods that we can call on the objects. "
   ]
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  {
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   "execution_count": null,
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   "outputs": [],
   "source": [
    "12.5.hex()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "x = 12.5\n",
    "print(f'{x.as_integer_ratio() = }')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "print(f'{12.5.as_integer_ratio() = }')"
   ]
  },
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   "metadata": {},
   "source": [
    "#### We can also import classes from modules such as `Decimal`. There are many classes we can import from the Python Standard Library. There are also contributed open-source modules that we can import to use their classes."
   ]
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   "cell_type": "markdown",
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   "source": [
    "### Importing Classes Account and Decimal\n",
    "#### In this example, we import custom class `Account` from module `account` defined in the Python source file `account.py` and class `Decimal` from module `decimal` in the Python Standard Library.\n",
    "#### We'll examine the definition of class `Account` after we see how it's used."
   ]
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   "source": [
    "from account import Account\n",
    "from decimal import Decimal"
   ]
  },
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Create an `Account` Object with a Constructor Expression\n",
    "#### To instantiate (create) an object from a class, use the name of the class followed by any required arguments."
   ]
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   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "account1 = Account('John Green', Decimal('50.00'))"
   ]
  },
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Getting an `Account`’s Name and Balance\n",
    "#### A class defines both methods and attributes for its objects. When we instantiated the `Account` object, we initialized its `name` and `balance` attributes. In doing so, we also instantiated and initialized a `Decimal` object."
   ]
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  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "account1.name"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "account1.balance"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Depositing Money into an `Account` \n",
    "#### Class `Account` defines a `deposit()` method for its objects."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "account1.deposit(Decimal('25.53'))\n",
    "account1.balance"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### `Account` Methods Perform Validation\n",
    "#### A class can define a method to perform validation."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "account1.deposit(Decimal('-123.45'))"
   ]
  },
  {
   "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 2024 by Ronald Mak"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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