Using normal python in makecode but it's not working

TEALS Intro CS
1

Hello, I am volunteering to help teach Intro to CS with Makecode. We are in unit 3 currently (of semester 1). I am looking ahead at the prospect of switching to python or typescript which I think happens in a later unit or even semester 2. I am testing makecode with some simple python code but finding it doesn’t seem to handle it well. The error it reports doesn’t make sense and it is referencing a javascript/typescript function. It looks to me like typescript may be the language it actually runs in? The code is pretty simple but doesn’t work. It works fine in VSCode or a typescript online repl if I change the game.splash() to print(). This is giving me doubts about using the makecode curriculum after it switches to python from blocks. Does anyone have any comments?

def naive(all_the_numbers, max_num):
    for outer in range(max_num):
        for inner in range(2, outer):
            if outer % inner == 0:
                all_the_numbers[outer] = False
                break

MAX_NUM = 15
all_the_numbers = [True]
for push_index in range(0, MAX_NUM):
    all_the_numbers.append(True)
naive(all_the_numbers, MAX_NUM)
     
for print_index in range(MAX_NUM - 1):
    if all_the_numbers[print_index] == True:
        game.splash(print_index)
2 Likes
2

Would you mind sharing the link to this project so I can take a look? It will help me understand the errors being suggested so I can get a better idea of what’s going on.

3

Hi, sorry I didn’t see your email til just now.

4

(it’s an example of a naive approach to finding prime numbers). I just grabbed it as some sample python to try in MakeCode.

5

This is a bug in MakeCode, I’ve filed an issue for it here: https://github.com/microsoft/pxt-arcade/issues/6320

As a workaround, you can fix it by adding a type hint to the all_the_numbers parameter like so:

def naive(all_the_numbers: List[bool], max_num):
    for outer in range(max_num):
        for inner in range(2, outer):
            if outer % inner == 0:
                all_the_numbers[outer] = False
                break

MAX_NUM = 15
all_the_numbers = [True]
for push_index in range(0, MAX_NUM):
    all_the_numbers.append(True)
naive(all_the_numbers, MAX_NUM)
     
for print_index in range(MAX_NUM - 1):
    if all_the_numbers[print_index] == True:
        game.splash(print_index)

note the : List[bool] after the all_the_numbers parameter

1 Like
6

Sorry, but playing around a little more I found something else. This line of code is reported as invalid, but it is also normal python:
all_the_numbers = [True] * MAX_NUM

(this would create an array of True booleans of length MAX_NUM)

MakeCode responds with an error message:
Line 9: types not compatible: boolean and number

7

I see that that fixes it. It seems like the Python in MakeCode is not vanilla Python, as I think is indicated in the docs. Is there documentation for the differences?

8

but i’m not sure those docs are complete. makecode python is referred to as “static python”, and it does not support everything in normal python

1 Like
9

The MakeCode Python documentation is limited. This cheat sheet for type hints in python has been helpful.

# Type hints cheat sheet

1 Like