freeCodeCamp/curriculum/challenges/english/07-scientific-computing-with-python/scientific-computing-with-python-projects/polygon-area-calculator.md

id, title, challengeType, forumTopicId, dashedName

id	title	challengeType	forumTopicId	dashedName
5e444147903586ffb414c94f	Polygon Area Calculator	23	462363	polygon-area-calculator

--description--

In this project you will use object oriented programming to create a Rectangle class and a Square class. The Square class should be a subclass of Rectangle, and inherit its methods and attributes.

Rectangle class

When a Rectangle object is created, it should be initialized with width and height attributes. The class should also contain the following methods:

• set_width
• set_height
• get_area: Returns area (width * height)
• get_perimeter: Returns perimeter (2 * width + 2 * height)
• get_diagonal: Returns diagonal ((width ** 2 + height ** 2) ** .5)
• get_picture: Returns a string that represents the shape using lines of "*". The number of lines should be equal to the height and the number of "*" in each line should be equal to the width. There should be a new line (\n) at the end of each line. If the width or height is larger than 50, this should return the string: "Too big for picture.".
• get_amount_inside: Takes another shape (square or rectangle) as an argument. Returns the number of times the passed in shape could fit inside the shape (with no rotations). For instance, a rectangle with a width of 4 and a height of 8 could fit in two squares with sides of 4.

Additionally, if an instance of a Rectangle is represented as a string, it should look like: Rectangle(width=5, height=10)

Square class

The Square class should be a subclass of Rectangle. When a Square object is created, a single side length is passed in. The __init__ method should store the side length in both the width and height attributes from the Rectangle class.

The Square class should be able to access the Rectangle class methods but should also contain a set_side method. If an instance of a Square is represented as a string, it should look like: Square(side=9)

Additionally, the set_width and set_height methods on the Square class should set both the width and height.

Usage example

rect = Rectangle(10, 5)
print(rect.get_area())
rect.set_height(3)
print(rect.get_perimeter())
print(rect)
print(rect.get_picture())

sq = Square(9)
print(sq.get_area())
sq.set_side(4)
print(sq.get_diagonal())
print(sq)
print(sq.get_picture())

rect.set_height(8)
rect.set_width(16)
print(rect.get_amount_inside(sq))

That code should return:

50
26
Rectangle(width=10, height=3)
**********
**********
**********

81
5.656854249492381
Square(side=4)
****
****
****
****

8

--hints--

The Square class should be a subclass of the Rectangle class.

({
  test: () => {
    pyodide.FS.writeFile('/home/pyodide/shape_calculator.py', code);
    pyodide.FS.writeFile('/home/pyodide/test_module.py',`
import unittest
import shape_calculator
from importlib import reload
reload(shape_calculator)
class UnitTests(unittest.TestCase):
    maxDiff = None
    
    def test_subclass(self):
        actual = issubclass(shape_calculator.Square, shape_calculator.Rectangle)
        expected = True
        self.assertEqual(actual, expected, 'Expected Square class to be a subclass of the Rectangle class.')    
`);
    const testCode = `
from unittest import main
from importlib import reload
import test_module
reload(test_module)
t = main(module='test_module', exit=False)
t.result.wasSuccessful()
`;
    const out = __pyodide.runPython(testCode);
    assert(out);
  }
})

The Square class should be a distinct class from the Rectangle class.

({
  test: () => {
    pyodide.FS.writeFile('/home/pyodide/shape_calculator.py', code);
    pyodide.FS.writeFile('/home/pyodide/test_module.py',`
import unittest
import shape_calculator
from importlib import reload
reload(shape_calculator)
class UnitTests(unittest.TestCase):
    maxDiff = None    
    
    def test_distinct_classes(self):
        actual = shape_calculator.Square is not shape_calculator.Rectangle
        expected = True
        self.assertEqual(actual, expected, 'Expected Square class to be a distinct class from the Rectangle class.')    
`);
    const testCode = `
from unittest import main
from importlib import reload
import test_module
reload(test_module)
t = main(module='test_module', exit=False)
t.result.wasSuccessful()
`;
    const out = __pyodide.runPython(testCode);
    assert(out);
  }
})

A square object should be an instance of the Square class and the Rectangle class.

({
  test: () => {
    pyodide.FS.writeFile('/home/pyodide/shape_calculator.py', code);
    pyodide.FS.writeFile('/home/pyodide/test_module.py',`
import unittest
import shape_calculator
from importlib import reload
reload(shape_calculator)
class UnitTests(unittest.TestCase):
    maxDiff = None
    def setUp(self):
        self.sq = shape_calculator.Square(5)
    
    def test_square_is_square_and_rectangle(self):
        actual = isinstance(self.sq, shape_calculator.Square) and isinstance(self.sq, shape_calculator.Rectangle)
        expected = True
        self.assertEqual(actual, expected, 'Expected square object to be an instance of the Square class and the Rectangle class.')    
`);
    const testCode = `
from unittest import main
from importlib import reload
import test_module
reload(test_module)
t = main(module='test_module', exit=False)
t.result.wasSuccessful()
`;
    const out = __pyodide.runPython(testCode);
    assert(out);
  }
})

The string representation of Rectangle(3, 6) should be Rectangle(width=3, height=6).

({
  test: () => {
    pyodide.FS.writeFile('/home/pyodide/shape_calculator.py', code);
    pyodide.FS.writeFile('/home/pyodide/test_module.py',`
import unittest
import shape_calculator
from importlib import reload
reload(shape_calculator)
class UnitTests(unittest.TestCase):
    maxDiff = None
    def setUp(self):
        self.rect = shape_calculator.Rectangle(3, 6)
    
    def test_rectangle_string(self):
        actual = str(self.rect)
        expected = "Rectangle(width=3, height=6)"
        self.assertEqual(actual, expected, 'Expected string representation of rectangle to be "Rectangle(width=3, height=6)"')    
`);
    const testCode = `
from unittest import main
from importlib import reload
import test_module
reload(test_module)
t = main(module='test_module', exit=False)
t.result.wasSuccessful()
`;
    const out = __pyodide.runPython(testCode);
    assert(out);
  }
})

The string representation of Square(5) should be Square(side=5).

({
  test: () => {
    pyodide.FS.writeFile('/home/pyodide/shape_calculator.py', code);
    pyodide.FS.writeFile('/home/pyodide/test_module.py',`
import unittest
import shape_calculator
from importlib import reload
reload(shape_calculator)
class UnitTests(unittest.TestCase):
    maxDiff = None
    def setUp(self):
        self.sq = shape_calculator.Square(5)
    
    def test_square_string(self):
        actual = str(self.sq)
        expected = "Square(side=5)"
        self.assertEqual(actual, expected, 'Expected string representation of square to be "Square(side=5)"')    
`);
    const testCode = `
from unittest import main
from importlib import reload
import test_module
reload(test_module)
t = main(module='test_module', exit=False)
t.result.wasSuccessful()
`;
    const out = __pyodide.runPython(testCode);
    assert(out);
  }
})

Rectangle(3, 6).get_area() should return 18.

({
  test: () => {
    pyodide.FS.writeFile('/home/pyodide/shape_calculator.py', code);
    pyodide.FS.writeFile('/home/pyodide/test_module.py',`
import unittest
import shape_calculator
from importlib import reload
reload(shape_calculator)
class UnitTests(unittest.TestCase):
    maxDiff = None
    def setUp(self):
        self.rect = shape_calculator.Rectangle(3, 6)
    
    def test_area(self):
        actual = self.rect.get_area()
        expected = 18
        self.assertEqual(actual, expected, 'Expected area of rectangle to be 18')    
`);
    const testCode = `
from unittest import main
from importlib import reload
import test_module
reload(test_module)
t = main(module='test_module', exit=False)
t.result.wasSuccessful()
`;
    const out = __pyodide.runPython(testCode);
    assert(out);
  }
})

Square(5).get_area() should return 25.

({
  test: () => {
    pyodide.FS.writeFile('/home/pyodide/shape_calculator.py', code);
    pyodide.FS.writeFile('/home/pyodide/test_module.py',`
import unittest
import shape_calculator
from importlib import reload
reload(shape_calculator)
class UnitTests(unittest.TestCase):
    maxDiff = None
    def setUp(self):
        self.sq = shape_calculator.Square(5)
    
    def test_area(self):        
        actual = self.sq.get_area()
        expected = 25
        self.assertEqual(actual, expected, 'Expected area of square to be 25')    
`);
    const testCode = `
from unittest import main
from importlib import reload
import test_module
reload(test_module)
t = main(module='test_module', exit=False)
t.result.wasSuccessful()
`;
    const out = __pyodide.runPython(testCode);
    assert(out);
  }
})

Rectangle(3, 6).get_perimeter() should return 18.

({
  test: () => {
    pyodide.FS.writeFile('/home/pyodide/shape_calculator.py', code);
    pyodide.FS.writeFile('/home/pyodide/test_module.py',`
import unittest
import shape_calculator
from importlib import reload
reload(shape_calculator)
class UnitTests(unittest.TestCase):
    maxDiff = None
    def setUp(self):
        self.rect = shape_calculator.Rectangle(3, 6)
    
    def test_perimeter(self):
        actual = self.rect.get_perimeter()
        expected = 18
        self.assertEqual(actual, expected, 'Expected perimeter of rectangle to be 18')    
`);
    const testCode = `
from unittest import main
from importlib import reload
import test_module
reload(test_module)
t = main(module='test_module', exit=False)
t.result.wasSuccessful()
`;
    const out = __pyodide.runPython(testCode);
    assert(out);
  }
})

Square(5).get_perimeter() should return 20.

({
  test: () => {
    pyodide.FS.writeFile('/home/pyodide/shape_calculator.py', code);
    pyodide.FS.writeFile('/home/pyodide/test_module.py',`
import unittest
import shape_calculator
from importlib import reload
reload(shape_calculator)
class UnitTests(unittest.TestCase):
    maxDiff = None
    def setUp(self):
        self.sq = shape_calculator.Square(5)
    
    def test_perimeter(self):
        actual = self.sq.get_perimeter()
        expected = 20
        self.assertEqual(actual, expected, 'Expected perimeter of square to be 20')    
`);
    const testCode = `
from unittest import main
from importlib import reload
import test_module
reload(test_module)
t = main(module='test_module', exit=False)
t.result.wasSuccessful()
`;
    const out = __pyodide.runPython(testCode);
    assert(out);
  }
})

Rectangle(3, 6).get_diagonal() should return 6.708203932499369.

({
  test: () => {
    pyodide.FS.writeFile('/home/pyodide/shape_calculator.py', code);
    pyodide.FS.writeFile('/home/pyodide/test_module.py',`
import unittest
import shape_calculator
from importlib import reload
reload(shape_calculator)
class UnitTests(unittest.TestCase):
    maxDiff = None
    def setUp(self):
        self.rect = shape_calculator.Rectangle(3, 6)
    
    def test_diagonal(self):
        actual = self.rect.get_diagonal()
        expected = 6.708203932499369
        self.assertEqual(actual, expected, 'Expected diagonal of rectangle to be 6.708203932499369')    
`);
    const testCode = `
from unittest import main
from importlib import reload
import test_module
reload(test_module)
t = main(module='test_module', exit=False)
t.result.wasSuccessful()
`;
    const out = __pyodide.runPython(testCode);
    assert(out);
  }
})

Square(5).get_diagonal() should return 7.0710678118654755.

({
  test: () => {
    pyodide.FS.writeFile('/home/pyodide/shape_calculator.py', code);
    pyodide.FS.writeFile('/home/pyodide/test_module.py',`
import unittest
import shape_calculator
from importlib import reload
reload(shape_calculator)
class UnitTests(unittest.TestCase):
    maxDiff = None
    def setUp(self):
        self.sq = shape_calculator.Square(5)
    
    def test_diagonal(self):
        actual = self.sq.get_diagonal()
        expected = 7.0710678118654755
        self.assertEqual(actual, expected, 'Expected diagonal of square to be 7.0710678118654755')    
`);
    const testCode = `
from unittest import main
from importlib import reload
import test_module
reload(test_module)
t = main(module='test_module', exit=False)
t.result.wasSuccessful()
`;
    const out = __pyodide.runPython(testCode);
    assert(out);
  }
})

An instance of the Rectangle class should have a different string representation after setting new values.

({
  test: () => {
    pyodide.FS.writeFile('/home/pyodide/shape_calculator.py', code);
    pyodide.FS.writeFile('/home/pyodide/test_module.py',`
import unittest
import shape_calculator
from importlib import reload
reload(shape_calculator)
class UnitTests(unittest.TestCase):
    maxDiff = None
    def setUp(self):
        self.rect = shape_calculator.Rectangle(3, 6)        
    
    def test_set_attributes(self):
        self.rect.set_width(7)
        self.rect.set_height(8)        
        actual = str(self.rect)
        expected = "Rectangle(width=7, height=8)"
        self.assertEqual(actual, expected, 'Expected string representation of rectangle after setting new values to be "Rectangle(width=7, height=8)"')    
`);
    const testCode = `
from unittest import main
from importlib import reload
import test_module
reload(test_module)
t = main(module='test_module', exit=False)
t.result.wasSuccessful()
`;
    const out = __pyodide.runPython(testCode);
    assert(out);
  }
})

An instance of the Square class should have a different string representation after setting new values by using .set_side().

({
  test: () => {
    pyodide.FS.writeFile('/home/pyodide/shape_calculator.py', code);
    pyodide.FS.writeFile('/home/pyodide/test_module.py',`
import unittest
import shape_calculator
from importlib import reload
reload(shape_calculator)
class UnitTests(unittest.TestCase):
    maxDiff = None
    def setUp(self):
        self.sq = shape_calculator.Square(5)
    
    def test_set_attributes(self):        
        self.sq.set_side(2)        
        actual = str(self.sq)
        expected = "Square(side=2)"
        self.assertEqual(actual, expected, 'Expected string representation of square after setting new values to be "Square(side=2)"')   
`);
    const testCode = `
from unittest import main
from importlib import reload
import test_module
reload(test_module)
t = main(module='test_module', exit=False)
t.result.wasSuccessful()
`;
    const out = __pyodide.runPython(testCode);
    assert(out);
  }
})

An instance of the Square class should have a different string representation after setting new values by using .set_width() or set_height().

({
  test: () => {
    pyodide.FS.writeFile('/home/pyodide/shape_calculator.py', code);
    pyodide.FS.writeFile('/home/pyodide/test_module.py',`
import unittest
import shape_calculator
from importlib import reload
reload(shape_calculator)
class UnitTests(unittest.TestCase):
    maxDiff = None
    def setUp(self):
        self.sq = shape_calculator.Square(5)
    
    def test_set_attributes(self):        
        self.sq.set_height(2)        
        actual = str(self.sq)
        expected = "Square(side=2)"
        self.assertEqual(actual, expected, 'Expected string representation of square after setting new values to be "Square(side=2)"')
        self.sq.set_width(4)
        actual = str(self.sq)
        expected = "Square(side=4)"
        self.assertEqual(actual, expected, 'Expected string representation of square after setting width to be "Square(side=4)"')    
`);
    const testCode = `
from unittest import main
from importlib import reload
import test_module
reload(test_module)
t = main(module='test_module', exit=False)
t.result.wasSuccessful()
`;
    const out = __pyodide.runPython(testCode);
    assert(out);
  }
})

The .get_picture() method should return a different string representation of a Rectangle instance.

({
  test: () => {
    pyodide.FS.writeFile('/home/pyodide/shape_calculator.py', code);
    pyodide.FS.writeFile('/home/pyodide/test_module.py',`
import unittest
import shape_calculator
from importlib import reload
reload(shape_calculator)
class UnitTests(unittest.TestCase):
    maxDiff = None
    def setUp(self):
        self.rect = shape_calculator.Rectangle(3, 6)
    
    def test_rectangle_picture(self):
        self.rect.set_width(7)
        self.rect.set_height(3)
        actual = self.rect.get_picture()
        expected = "*******\\n*******\\n*******\\n"
        self.assertEqual(actual, expected, 'Expected rectangle picture to be different.')    
`);
    const testCode = `
from unittest import main
from importlib import reload
import test_module
reload(test_module)
t = main(module='test_module', exit=False)
t.result.wasSuccessful()
`;
    const out = __pyodide.runPython(testCode);
    assert(out);
  }
})

The .get_picture() method should return a different string representation of a Square instance.

({
  test: () => {
    pyodide.FS.writeFile('/home/pyodide/shape_calculator.py', code);
    pyodide.FS.writeFile('/home/pyodide/test_module.py',`
import unittest
import shape_calculator
from importlib import reload
reload(shape_calculator)
class UnitTests(unittest.TestCase):
    maxDiff = None
    def setUp(self):
        self.sq = shape_calculator.Square(5)
    
    def test_square_picture(self):
        self.sq.set_side(2)
        actual = self.sq.get_picture()
        expected = "**\\n**\\n"
        self.assertEqual(actual, expected, 'Expected square picture to be different.')    
`);
    const testCode = `
from unittest import main
from importlib import reload
import test_module
reload(test_module)
t = main(module='test_module', exit=False)
t.result.wasSuccessful()
`;
    const out = __pyodide.runPython(testCode);
    assert(out);
  }
})

The .get_picture() method should return the string Too big for picture. if the width or height attributes are larger than 50.

({
  test: () => {
    pyodide.FS.writeFile('/home/pyodide/shape_calculator.py', code);
    pyodide.FS.writeFile('/home/pyodide/test_module.py',`
import unittest
import shape_calculator
from importlib import reload
reload(shape_calculator)
class UnitTests(unittest.TestCase):
    maxDiff = None
    def setUp(self):
        self.rect = shape_calculator.Rectangle(3, 6)
    
    def test_big_picture(self):
        self.rect.set_width(51)
        self.rect.set_height(3)
        actual = self.rect.get_picture()
        expected = "Too big for picture."
        self.assertEqual(actual, expected, 'Expected message: "Too big for picture."')    
`);
    const testCode = `
from unittest import main
from importlib import reload
import test_module
reload(test_module)
t = main(module='test_module', exit=False)
t.result.wasSuccessful()
`;
    const out = __pyodide.runPython(testCode);
    assert(out);
  }
})

Rectangle(15,10).get_amount_inside(Square(5)) should return 6.

({
  test: () => {
    pyodide.FS.writeFile('/home/pyodide/shape_calculator.py', code);
    pyodide.FS.writeFile('/home/pyodide/test_module.py',`
import unittest
import shape_calculator
from importlib import reload
reload(shape_calculator)
class UnitTests(unittest.TestCase):
    maxDiff = None
    def setUp(self):
        self.rect = shape_calculator.Rectangle(3, 6)
        self.sq = shape_calculator.Square(5)
    
    def test_get_amount_inside(self):
        self.rect.set_height(10)
        self.rect.set_width(15)
        actual = self.rect.get_amount_inside(self.sq)
        expected = 6
        self.assertEqual(actual, expected, 'Expected "get_amount_inside" to return 6.')    
`);
    const testCode = `
from unittest import main
from importlib import reload
import test_module
reload(test_module)
t = main(module='test_module', exit=False)
t.result.wasSuccessful()
`;
    const out = __pyodide.runPython(testCode);
    assert(out);
  }
})

Rectangle(4,8).get_amount_inside(Rectangle(3, 6)) should return 1.

({
  test: () => {
    pyodide.FS.writeFile('/home/pyodide/shape_calculator.py', code);
    pyodide.FS.writeFile('/home/pyodide/test_module.py',`
import unittest
import shape_calculator
from importlib import reload
reload(shape_calculator)
class UnitTests(unittest.TestCase):
    maxDiff = None
    def setUp(self):
        self.rect = shape_calculator.Rectangle(3, 6)
    
    def test_get_amount_inside_two_rectangles(self):
        rect2 = shape_calculator.Rectangle(4, 8)
        actual = rect2.get_amount_inside(self.rect)
        expected = 1
        self.assertEqual(actual, expected, 'Expected "get_amount_inside" to return 1.')    
`);
    const testCode = `
from unittest import main
from importlib import reload
import test_module
reload(test_module)
t = main(module='test_module', exit=False)
t.result.wasSuccessful()
`;
    const out = __pyodide.runPython(testCode);
    assert(out);
  }
})

Rectangle(2,3).get_amount_inside(Rectangle(3, 6)) should return 0.

({
  test: () => {
    pyodide.FS.writeFile('/home/pyodide/shape_calculator.py', code);
    pyodide.FS.writeFile('/home/pyodide/test_module.py',`
import unittest
import shape_calculator
from importlib import reload
reload(shape_calculator)
class UnitTests(unittest.TestCase):
    maxDiff = None
    def setUp(self):
        self.rect = shape_calculator.Rectangle(3, 6)
    
    def test_get_amount_inside_none(self):
        rect2 = shape_calculator.Rectangle(2, 3)
        actual = rect2.get_amount_inside(self.rect)
        expected = 0
        self.assertEqual(actual, expected, 'Expected "get_amount_inside" to return 0.')    
`);
    const testCode = `
from unittest import main
from importlib import reload
import test_module
reload(test_module)
t = main(module='test_module', exit=False)
t.result.wasSuccessful()
`;
    const out = __pyodide.runPython(testCode);
    assert(out);
  }
})

--seed--

--seed-contents--

class Rectangle:
    pass

class Square:
    pass

--solutions--

class Rectangle:
    def __init__(self, width, height):
        self.width = width
        self.height = height

    def __str__(self):
        return f'Rectangle(width={self.width}, height={self.height})'

    def set_width(self, width):
        self.width = width
    
    def set_height(self, height):
        self.height = height

    def get_area(self):
        area = self.width * self.height
        return area

    def get_perimeter(self):
        perimeter = self.width * 2 + self.height * 2
        return perimeter
    
    def get_diagonal(self):
        diagonal = (self.width ** 2 + self.height ** 2) ** 0.5        
        return diagonal
    
    def get_picture(self):
        if self.width < 50 and self.height < 50:
            picture = f'{"*"*self.width}\n'*self.height            
            return picture
        else:            
            return 'Too big for picture.'
    
    def get_amount_inside(self, polygon):
        h_number = self.height // polygon.height
        w_number = self.width // polygon.width
        repetition = h_number * w_number        
        return repetition
        

class Square(Rectangle):
    def __init__(self, side):
        self.width = side
        self.height = side

    def __str__(self):
        return f'Square(side={self.width})'
    
    def set_width(self, side):
        self.width = side
        self.height = side
    
    def set_height(self, side):
        self.height = side
        self.width = side
    
    def set_side(self,side):
        self.width = side
        self.height = side