Types and Conversion

Every value has a type. The types so far: int, float, and str (string). The type function reports a value's type:

print(type(42))
print(type(4.5))
print(type("42"))

Output:

<class 'int'>
<class 'float'>
<class 'str'>

The last line matters: "42" is a string, not a number. Arithmetic on it fails or misbehaves — "42" + "1" is "421", not 43.

Three functions convert between types:

• int(x) converts to a whole number: int("42") is 42.
• float(x) converts to a decimal number: float("19.99") is 19.99.
• str(x) converts to a string: str(50) is "50".

count_text = "42"
count = int(count_text)
print(count + 8)

Output:

50

int fails if the text is not a whole number: int("4.5") and int("hello") are errors.

Exercise

The starter code creates count_text and price_text, both strings.

1. Create count — count_text converted to an int.
2. Create price — price_text converted to a float.
3. Create total holding count + 8.
4. Create label — total converted to a string.
5. Print total and its type.

Run your code to see the output, then press Submit.

Tests

import unittest


class TestTypesAndConversion(unittest.TestCase):
    def test_count_is_the_int_42(self):
        self.assertEqual(count, 42)
        self.assertIsInstance(count, int)

    def test_price_is_the_float_19_99(self):
        self.assertEqual(price, 19.99)
        self.assertIsInstance(price, float)

    def test_total_is_50(self):
        self.assertEqual(total, 50)

    def test_label_is_the_string_50(self):
        self.assertEqual(label, "50")
        self.assertIsInstance(label, str)