Simple Python console program asking questions

Question

I'm trying to create this program

• Print a welcome message, and then prompt the user to select a difficulty by entering 1, 2 or 3.
• Use a loop to re-prompt the user until a valid response (1, 2 or 3) is entered.

Once a difficulty has been selected, print a message confirming the selected difficulty and set variables as follows:

• 1 was chosen:
  lives = 3, max_num = 10 and questions = 5

• 2 chosen:
  lives = 2, max_num = 25 and questions = 10

• 3 was chosen:
  lives = 1, max_num = 50 and questions = 15

lives represents how many incorrect answers are permitted.
max_num represents the largest number enter code here used when generating a question.
questions represents the number of questions

The code below is what i have done so far

def input_valid_difficulty(prompt=''):
    while True:
        try:
            n = int(input(prompt))
            if n < 0 or n > 3:
                raise ValueError
                break
        except ValueError:
            print("Invalid choice! Enter 1,2 or 3.")
            prompt = "Select a difficulty?: (0 to exit):"
    return n

difficulty = input_valid_difficulty ("Select a difficulty?: (0 to exit):")
if difficulty == 0:
    quit()
elif difficulty == 1:
    print("Easy mode selected!")
elif difficulty == 2:
    print("Medium mode selected!")
elif difficulty == 3:
    print("Hard mode selected!")

Answer 1

Here's an example of generating a game you descibed.

from random import sample

def input_valid_difficulty(prompt=''):
    while True:
        try:
            n = int(input(prompt))
            if n < 0 or n > 3:
                raise ValueError
            break
        except ValueError:
            print("Invalid choice! Enter 1,2 or 3.")
            prompt = "Select a difficulty?: (0 to exit):"
    return n

# Setup Difficult & Lives
difficulty = input_valid_difficulty ("Select a difficulty?: (0 to exit):")
if difficulty == 0:
    quit()
elif difficulty == 1:
    print("Easy mode selected!")
    lives, max_num, questions = 3, 10, 5
elif difficulty == 2:
    print("Medium mode selected!")
    lives, max_num, questions = 2, 25, 10
elif difficulty == 3:
    print("Hard mode selected!")
    lives, max_num, questions = 1, 50, 15

# Following line generates a list of 800 questions to choose from
operations = ['+', '-']  # testing addition and subtraction

#all_q_and_a = [(f"{i} {op} {j} = ?: ", eval(f"{i} {op} {j}")) for i in range(20) \
#                      for j in range(20) for op in operations]
# Following equivalent to above list comprehension
all_q_and_a = []
for i in range(20):
  for j in range(20):
    for op in operations:
      all_q_and_a.append((f"{i} {op} {j} = ?: ", eval(f"{i} {op} {j}")))

# Select random questions from list of all questions at random (note: 'questions' tells us how many questions to ask)
# 'Sample' selects a random list of unique questions from complete list
chosen_q_and_a = sample(all_q_and_a, questions)

# We now have a random set of questions and answers to present to 
# the user.  An example would be:
# [('18 + 19 = ?: ', 37), ('4 + 12 = ?: ', 16), ('8 + 2 = ?: ', 10), ('4 - 2 = ?: ', 2), ('1 + 3 = ?: ', 4)]

score = 0
for q in chosen_q_and_a:
  if lives == 0:
    break
  while lives > 0:
    answer = int(input(q[0]))
    if answer == q[1]:
      print("Correct")
      score += max_num  # increase score according to max_num 
                        #(wasn't sure if there was any
                        #other use of this variable)
      break
    else:
      lives -= 1
      print("Sorry, try again")

print(f"Your score was {score}")