Summary  
This chapter introduces how to declare, assign, and reassign variables to store and manage different data types, and how to access those values using printing.

General domain of usage  
Inventory management

We'll explore **how to store data inside variables**, much like organizing your groceries into the right bins. This makes your data **easy to access** and manipulate – key to any efficient coding project.

Watch Alex as he demonstrates how to store data in variables:

Let's put this into practice. Here, we're assigning **various types of data** to variables, each representing different aspects of a grocery item.


# Storing different types of data in variables
item_name = "Banana"
item_price = 0.50
item_stock_quantity = 100
in_stock = True

print("Item:", item_name)
print("Price: $", item_price)
print("Quantity:", item_stock_quantity)
print("In stock:", in_stock)

This example shows how easily you can **access and display the data** once it's stored in variables. Notice how each variable type (`string`, `float`, `integer`, `boolean`) serves a specific purpose in our grocery analogy.

## Reassigning Variables

Once a **variable is created**, you can change its value at any time. This is called **reassigning a variable** – the **old value** gets replaced with a **new one**.

item_name = "Banana"
print("Item:", item_name)

# Reassigning the variable
item_name = "Apple"
print("Item:", item_name)

Here, you first store **"Banana"** in `item_name`, and later replace it with **"Apple"**. The variable itself stays the same, but its content is updated.

import unittest
import user_code
from io import StringIO
from contextlib import redirect_stdout
import importlib
import re


def _dynamic_test(test_case, condition, success_message, failure_message):
    if condition:
        test_case._testMethodName = success_message
        test_case.assertTrue(True, success_message)
    else:
        test_case._testMethodName = failure_message
        test_case.fail(failure_message)


class TestUserCode(unittest.TestCase):
    def normalize_text(self, text):
        text = text.lower()
        text = re.sub(r'\s*:\s*', ':', text)
        text = re.sub(r'\s+', ' ', text)
        return text.strip()

    def test_item_name_declared(self):
        _dynamic_test(
            self,
            hasattr(user_code, 'item_name'),
            'item_name is declared',
            'Expected item_name to be defined.'
        )

    def test_item_name_correct(self):
        _dynamic_test(
            self,
            user_code.item_name == "Eggs",
            "item_name equals 'Eggs'",
            f"Expected item_name to equal 'Eggs', but got {user_code.item_name}."
        )

    def test_item_price_declared(self):
        _dynamic_test(
            self,
            hasattr(user_code, 'item_price'),
            'item_price is declared',
            'Expected item_price to be defined.'
        )

    def test_item_price_correct(self):
        _dynamic_test(
            self,
            user_code.item_price == 3.99,
            'item_price equals 3.99',
            f"Expected item_price to equal 3.99, but got {user_code.item_price}."
        )

    def test_item_stock_quantity_declared(self):
        _dynamic_test(
            self,
            hasattr(user_code, 'item_stock_quantity'),
            'item_stock_quantity is declared',
            'Expected item_stock_quantity to be defined.'
        )

    def test_item_stock_quantity_correct(self):
        _dynamic_test(
            self,
            user_code.item_stock_quantity == 120,
            'item_stock_quantity equals 120',
            f"Expected item_stock_quantity to equal 120, but got {user_code.item_stock_quantity}."
        )

    def test_in_stock_declared(self):
        _dynamic_test(
            self,
            hasattr(user_code, 'in_stock'),
            'in_stock is declared',
            'Expected in_stock to be defined.'
        )

    def test_in_stock_correct(self):
        _dynamic_test(
            self,
            isinstance(user_code.in_stock, bool) and user_code.in_stock is True,
            'in_stock is a boolean and equals True',
            f"Expected in_stock to be of type bool and equal to True, but got {user_code.in_stock} of type {type(user_code.in_stock)}."
        )

if __name__ == '__main__':
    unittest.main()

test_main.py

A streamlined beginner course focusing on the core programming concepts in Python as a foundation for data science. This version removes recap chapters to maintain an action-oriented, hands-on learning experience with a focus on writing clean code, manipulating variables, controlling program flow, building reusable functions, and utilizing fundamental data structures, each reinforced by practical challenges.

Storing Data in Variables

Reassigning Variables

Solução