In the preceding chapter, it appeared that we were counting letters to determine the index corresponding to each letter. If we intend to access the final symbol, manual counting may seem cumbersome.

Python, however, is considerate and anticipates our needs. Consequently, it introduced **negative indexing**. To obtain the last character of a word, it is advisable to utilize the syntax `word[-1]`.

> Note
>
> The negative indexation starts from -1, then -2, etc. `word[-0]` is the same as `word[0]` for Python.

**A small piece of advice**: We can mentally divide a string into two parts and use positive indexation for the left-hand part and negative indexation for the right-hand part, but it's always up to us.😏

import unittest
import sys
from io import StringIO


class TestUserCode(unittest.TestCase):
    def _test_variable_equals_string(self, var_name, expected):
        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 var != expected:
            return (False, f"Expected '{var_name}' to equal '{expected}', but got '{var}'.")
        return (True, f'The variable {var_name} equals "{expected}"')

    def test_a(self):
        passed, result_text = self._test_variable_equals_string(
            'a', 'a')
        self._testMethodName = result_text
        self.assertTrue(passed, result_text)

    def test_g(self):
        passed, result_text = self._test_variable_equals_string(
            'g', 'g')
        self._testMethodName = result_text
        self.assertTrue(passed, result_text)

    def test_e(self):
        passed, result_text = self._test_variable_equals_string(
            'e', 'e')
        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.

The main goal of this section is to clarify the boolean data types; it's a sub type of numeric data, but indeed it is more challenging. Since it is always better to excel in the more difficult topics, this section is a valuable part of your curriculum.

Strings are a way for us to implement your phrases in Python, that is, to give instructions to users who are the target audience of your program. Indeed, it is always better to be able to work with strings because they should be used in your code. You'll understand why soon.

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

Data Types in Python

Negative Indexation

Solution

Negative Indexation

Solution