Summary  
This chapter explains how to declare variables, assign them values of various data types, and reassign those values to update stored data in your code.

General domain of usage  
Grocery inventory management

**Brilliant work** mastering data types! Next, 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

Gain a solid foundation in Python for data analysis. Learn to work with variables, data types, strings, conditional statements, loops, core data structures, and functions using examples relevant to analytical tasks.

Storing Data in Variables

Reassigning Variables

Oplossing