Summary  
This chapter demonstrates how to use the str() function to convert non-string values into strings for concatenation in code.

General domain of usage  
Formatting printed output

As you remember, the following text leads to an error:

To implement concatenation here, we can just put `20` in quotes, like `"20"`, but this solution doesn't look beautiful program-wise.

Hence, your work will be more fruitful if we can convert everything into strings. Here, the `str()` function should be implemented:

> Note
>
> The syntax of this operation may appear familiar, resembling that of the `int()` or` float()` functions. In reality, it is identical, as it involves converting an argument into a string using the `str()` function.

import unittest


class ExpectedType:
    def __init__(self, expected_type, name):
        self.expected_type = expected_type
        self.name = name


class TestUserCode(unittest.TestCase):
    def _test_variable_equals(self, var_name, expected, expected_type=None):
        import user_code
        if not hasattr(user_code, var_name):
            return (False, f"Expected '{var_name}' variable to be defined.")
        var = getattr(user_code, var_name)

        if (expected_type is not None) and (not isinstance(var, expected_type.expected_type)):
            return (False, f"Expected '{var_name}' to be of type '{expected_type.name}', but got '{type(var).__name__}'.")

        if var != expected:
            return (False, f"Expected '{var_name}' to equal '{expected}', but got '{str(var)}'.")
        return (True, f'The variable {var_name} equals "{expected}"')

    def test_vertices(self):
        passed, result_text = self._test_variable_equals(
            'vertices', '5', expected_type=ExpectedType(str, 'str'))
        self._testMethodName = result_text
        self.assertTrue(passed, result_text)

    def test_cards(self):
        passed, result_text = self._test_variable_equals(
            'cards', '22', expected_type=ExpectedType(str, 'str'))
        self._testMethodName = result_text
        self.assertTrue(passed, result_text)

    def test_largest_number(self):
        passed, result_text = self._test_variable_equals(
            'largest_number', '128', expected_type=ExpectedType(str, 'str'))
        self._testMethodName = result_text
        self.assertTrue(passed, result_text)


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


test_main.py

This course is going to help you dive deeper into data types and try to work with them. Here you will learn basic operations and all ins and outs of numbers, boolean data type, and strings. This course consists of a lot of practical tasks after which you will become a skillful programmer.

Numeric data types are crucial in Python, so it is important to start with them. Here you will work with simple math operations and find out the purposes of learning different types of numerical data.

Mastering boolean data types and logical operations in Python. You'll learn how to work with True and False, apply logical operators like and, or, and not, and understand how operator precedence works in complex expressions.

Strings are an essential part of Python programming, allowing you to work with text data. In this section, you'll learn how to manipulate strings, extract characters, slice words, and search for specific phrases.

This chapter consists of practical tasks that combine all the examined topics together with a bit of theory.

Converting: str()

Lösung

Awesome!

Converting: str()

Lösung

Awesome!