In the preceding chapter, we discussed the method for extracting a particular character from a string. However, what procedures can we employ to obtain a particular substring with a consecutive sequence of characters? The most straightforward approach is to employ a technique called **slicing**.

This operation allows us to get not only one symbol, but a combination of symbols per operation. Take a look at the syntax:

string = "Extract the word kitten"
kitten = string[17:23]
print(kitten)

The syntax is `string[starting_index : ending_index]`, but try to **double check the indexation** for the word `kitten`. 

`k` has an index of `17`, but the `n` character has an index of `22`, not `23`. 

**Why was 23 written?**

The solution is straightforward. The ending index is **exclusive**, meaning that when we write 23, Python does not include this index but considers the one immediately before it.

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_puppy_declared(self):
        passed, result_text = self._test_variable_equals_string('puppy', 'puppy')
        self._testMethodName = result_text
        self.assertTrue(passed, result_text)

    def test_nestling_declared(self):
        passed, result_text = self._test_variable_equals_string('nestling', 'nestling')
        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.

Slice the Word

Solution