Simple math problems for practice

problems.py

#!/usr/bin/env python3
#-*- coding: utf-8 -*-

from functools import reduce
import operator
from random import randrange

from typing import Sequence

PROMPT = "What's the answer? "
GOODBYE = "\n\n *** Thanks for playing! ***"


# colors - stolen from https://stackoverflow.com/a/287944/7376
class bcolors:
    HEADER = '\033[95m'
    OKBLUE = '\033[94m'
    OKCYAN = '\033[96m'
    OKGREEN = '\033[92m'
    WARNING = '\033[93m'
    FAIL = '\033[91m'
    ENDC = '\033[0m'
    BOLD = '\033[1m'
    UNDERLINE = '\033[4m'


def random_problem(minimum: int, maximum: int,
                   number_of_terms: int, sign: str) -> None:
    """
    Generate a series (of length number_of_terms) of numbers between
    minimum and maximum for the given problem type and check the work
    """
    if number_of_terms < 2:
        raise SystemExit(f"Looks like someone made a mistake here! "
                         f"Please fix the difficulty: terms for {sign}")
    terms = sorted(
        [randrange(minimum, maximum) for _ in range(number_of_terms)],
        key=int, reverse=True
    )
    math_operation = {
        "+": operator.add,
        "x": operator.mul,
        "/": operator.truediv,
        "-": operator.sub
    }[sign]
    format_problem(sign, *terms)
    answer = input(PROMPT)
    attempt = 1
    correct_answer = reduce(lambda x, y: math_operation(x, y), terms)
    while not get_result(answer, correct_answer):
        answer = input(PROMPT)
        attempt += 1
        if attempt % 3 == 0:
            get_hint(sign, terms, correct_answer)


def get_result(attempt: str, answer: int) -> bool:
    """
    See if the user got the correct answer or if they want to quit or skip
    """
    try:
        if int(attempt) == answer:
            print(f"{bcolors.OKGREEN}Correct! Let's try another!\n{bcolors.ENDC}")
            return True
    except ValueError:
        inp = attempt.lower()
        if inp == "q":
            raise SystemExit(GOODBYE)
        if inp == "s":
            print("No problem, on to the next one!")
            return True
        print(f"{bcolors.FAIL}Please type a number!{bcolors.ENDC}")
        return False
    print(f"{bcolors.WARNING}Try again{bcolors.ENDC}")
    return False


def get_hint(sign: str, terms: Sequence[int], correct_answer: int) -> None:
    """
    In the most horribly sloppy fashion, provide hints for the problem type.
    If the answer is less than 1 (because the author made 0 attempt to prevent
    it) give the poor dummy an out.
    """
    if correct_answer < 1:
        print(f"{bcolors.WARNING}Hmm, this looks like a hard one. "
              f"Type {bcolors.OKCYAN}s {bcolors.WARNING}to skip{bcolors.ENDC}")
        return
    if sign == "+":
        if max(terms) > 10:
            print("Slow down and write it out on your whiteboard or paper")
        else:
            print("If I have " + terms[0] * "🍎" + " and someone gives me")
            for t in terms[1:]:
                print(t * "🍎")
            print("How many apples do I have?")
    if sign == "-":
        print("The answer to subtraction is the difference between the numbers. Maybe this will help")
        for i, t in enumerate(terms):
            color = bcolors.OKBLUE if i % 2 else bcolors.OKGREEN
            print(color + "." * t + bcolors.ENDC)
    if sign == "/":
        print("You don't know how to do this yet! Stop guessing :)")
    if sign == "x":
        x, y = terms[:2]
        print(f"Think of this as {y} groups of {x}")
        for _ in range(y):
            print("." * x)


def format_problem(sign: str, *args):
    # TODO: stop cheating and handle right-padding
    max_width = len(str(max(args)))
    for a in args[:-1]:
        print(f" {a}")
    print(sign + str(args[-1]))
    print("-" * (max_width + 1))


"""
Set the level of difficulty per type of problem
"""
difficulty = {
    "+": {
        "minimum": 10,
        "maximum": 90,
        "number_of_terms": 2
    },
    "-": {
        "minimum": 10,
        "maximum": 90,
        "number_of_terms": 2
    },
    "x": {
        "minimum": 1,
        "maximum": 9,
        "number_of_terms": 2
    },
    "/": {
        "minimum": 1,
        "maximum": 9,
        "number_of_terms": 2
    }
}


if __name__ == '__main__':
    print("Welcome to the Mathalympics, let's see how you're doing")
    print("Press q to quit and you can always press s to skip if you're stuck")
    print("Do you want to do Addition (+), Subtraction (-), Multiplication (x) or Division (/)?")
    sign = None
    while not sign:
        choices = difficulty.keys()
        choice = input(f"Enter {' or '.join(choices)} ")
        if choice in choices:
            sign = choice
    try:
        while True:
            kwargs = difficulty[sign]
            kwargs["sign"] = sign
            random_problem(**kwargs)
    except KeyboardInterrupt:
        print(GOODBYE)

Should make reverse=True on the sorting an optional parameter by operation type as things like fractions will want to be sorted in ascending order.