This is just about basic numpy operator, requires a bit of discovering.
Time for this problem: 35m (5m for the code, 30 to make the test work in notebook format)
Content of this section is copied and reformatted from this repl.it, so that you can understand what the code does (and I get to render a nice contentful page).
Create a function named calculate() in mean_var_std.py that uses Numpy to
output the mean, variance, standard deviation, max, min, and sum of the rows,
columns, and elements in a 3 x 3 matrix.
The input of the function should be a list containing 9 digits. The function should convert the list into a 3 x 3 Numpy array, and then return a dictionary containing the mean, variance, standard deviation, max, min, and sum along both axes and for the flattened matrix.
The returned dictionary should follow this format:
{
'mean': [axis1, axis2, flattened],
'variance': [axis1, axis2, flattened],
'standard deviation': [axis1, axis2, flattened],
'max': [axis1, axis2, flattened],
'min': [axis1, axis2, flattened],
'sum': [axis1, axis2, flattened]
}
If a list containing less than 9 elements is passed into the function, it
should raise a ValueError exception with the message: "List must contain
nine numbers." The values in the returned dictionary should be lists and not
Numpy arrays.
For example, calculate([0,1,2,3,4,5,6,7,8]) should return:
{
'mean': [[3.0, 4.0, 5.0], [1.0, 4.0, 7.0], 4.0],
'variance': [[6.0, 6.0, 6.0], [0.6666666666666666, 0.6666666666666666, 0.6666666666666666], 6.666666666666667],
'standard deviation': [[2.449489742783178, 2.449489742783178, 2.449489742783178], [0.816496580927726, 0.816496580927726, 0.816496580927726], 2.581988897471611],
'max': [[6, 7, 8], [2, 5, 8], 8],
'min': [[0, 1, 2], [0, 3, 6], 0],
'sum': [[9, 12, 15], [3, 12, 21], 36]
}
The unit tests for this project are in test_module.py.
For development, you can use main.py to test your calculate() function.
Click the "run" button and main.py will run.
We imported the tests from test_module.py to main.py for your convenience.
The tests will run automatically whenever you hit the "run" button.
Copy your project's URL and submit it to freeCodeCamp.
from pprint import pprint
import numpy as np
def calculate(arr):
if len(arr) != 9:
raise ValueError("List must contain nine numbers.")
m = np.array(arr).reshape([3, 3])
r = {
"mean": [m.mean(0).tolist(), m.mean(1).tolist(), m.mean()],
"variance": [m.var(0).tolist(), m.var(1).tolist(), m.var()],
"standard deviation": [m.std(0).tolist(), m.std(1).tolist(), m.std()],
"max": [m.max(0).tolist(), m.max(1).tolist(), m.max()],
"min": [m.min(0).tolist(), m.min(1).tolist(), m.min()],
"sum": [m.sum(0).tolist(), m.sum(1).tolist(), m.sum()],
}
return r
pprint(calculate([i for i in range(0, 9)]))
The test code is provided by FCC, in the repl.it link. I modified it a bit to make it runnable in notebook.
import unittest
class UnitTests(unittest.TestCase):
def test_calculate(self):
actual = calculate([2, 6, 2, 8, 4, 0, 1, 5, 7])
expected = {
"mean": [
[3.6666666666666665, 5.0, 3.0],
[3.3333333333333335, 4.0, 4.333333333333333],
3.888888888888889,
],
"variance": [
[9.555555555555557, 0.6666666666666666, 8.666666666666666],
[3.555555555555556, 10.666666666666666, 6.222222222222221],
6.987654320987654,
],
"standard deviation": [
[3.091206165165235, 0.816496580927726, 2.943920288775949],
[1.8856180831641267, 3.265986323710904, 2.494438257849294],
2.6434171674156266,
],
"max": [[8, 6, 7], [6, 8, 7], 8],
"min": [[1, 4, 0], [2, 0, 1], 0],
"sum": [[11, 15, 9], [10, 12, 13], 35],
}
self.assertAlmostEqual(
actual,
expected,
"Expected different output when calling 'calculate()' with '[2,6,2,8,4,0,1,5,7]'",
)
def test_calculate2(self):
actual = calculate([9, 1, 5, 3, 3, 3, 2, 9, 0])
expected = {
"mean": [
[4.666666666666667, 4.333333333333333, 2.6666666666666665],
[5.0, 3.0, 3.6666666666666665],
3.888888888888889,
],
"variance": [
[9.555555555555555, 11.555555555555557, 4.222222222222222],
[10.666666666666666, 0.0, 14.888888888888891],
9.209876543209875,
],
"standard deviation": [
[3.0912061651652345, 3.39934634239519, 2.0548046676563256],
[3.265986323710904, 0.0, 3.8586123009300755],
3.0347778408328137,
],
"max": [[9, 9, 5], [9, 3, 9], 9],
"min": [[2, 1, 0], [1, 3, 0], 0],
"sum": [[14, 13, 8], [15, 9, 11], 35],
}
self.assertAlmostEqual(
actual,
expected,
"Expected different output when calling 'calculate()' with '[9,1,5,3,3,3,2,9,0]'",
)
def test_calculate_with_few_digits(self):
self.assertRaisesRegex(
ValueError,
"List must contain nine numbers.",
calculate,
[
2,
6,
2,
8,
4,
0,
1,
],
)
if __name__ == "__main__":
unittest.main(argv=["first-arg-is-ignored"], exit=False)