Summary  
This chapter covers using the built-in len() function to calculate the number of characters in a string, counting every character including spaces and punctuation.

General domain of usage  
Input validation

Сalculating the number of characters in a string is a common operation. It helps in tasks like validation, formatting, or data analysis. Python provides a built-in function `len()` to get the length of a string.

```python
len(string)
```

The `string` parameter refers to the text whose length you want to determine; the `len()` function returns the total number of characters in that text, including spaces and punctuation marks.

string = "Practice is the key to success"
length = len(string)

print("Here is the string:", string)
print("And its length is", length)

The `len()` function counts every character in the string, including spaces. In the example, `"Practice is the key to success"` has 30 characters, so `len(text)` returns 30.

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_symbol1(self):
        passed, result_text = self._test_variable_equals_string(
            'symbol1', 'd')
        self._testMethodName = result_text
        self.assertTrue(passed, result_text)

    def test_symbol2(self):
        passed, result_text = self._test_variable_equals_string(
            'symbol2', 'd')
        self._testMethodName = result_text
        self.assertTrue(passed, result_text)


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


test_main.py

A focused, beginner-friendly course on working with numbers in Python. Learn about integers, floats, arithmetic operations, type conversion, and how to avoid common pitfalls when handling numerical data.

String Length

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