I making a quiz program using Python 3. I'm trying to implement checks so that if the user enters a string, the console won't spit out errors. The code I've put in doesn't work, and I'm not sure how to go about fixing it.

import random
import operator
operation=[(operator.add, "+"),(operator.mul, "*"),(operator.sub, "-")]
num_of_q=10
score=0
name=input("What is your name? ")
class_num =input("Which class are you in? ")
print(name,", welcome to this maths test!")for _ in range(num_of_q):num1=random.randint(0,10)num2=random.randint(1,10)op,symbol=random.choice(operation)print("What is",num1,symbol,num2,"?")if int(input()) == op(num1, num2):print("Correct")score += 1try:val = int(input())except ValueError:print("That's not a number!")else:print("Incorrect")if num_of_q==10:print(name,"you got",score,"/",num_of_q)

You need to catch the exception already in the first if clause. For example:

for _ in range(num_of_q):num1=random.randint(0,10)num2=random.randint(1,10)op,symbol=random.choice(operation)print("What is",num1,symbol,num2,"?")try:outcome = int(input())except ValueError:print("That's not a number!")else:if outcome == op(num1, num2):print("Correct")score += 1else:print("Incorrect")

I've also removed the val = int(input()) clause - it seems to serve no purpose.

EDIT

If you want to give the user more than one chance to answer the question, you can embed the entire thing in a while loop:

for _ in range(num_of_q):num1=random.randint(0,10)num2=random.randint(1,10)op,symbol=random.choice(operation)while True:print("What is",num1,symbol,num2,"?")try:outcome = int(input())except ValueError:print("That's not a number!")else:if outcome == op(num1, num2):print("Correct")score += 1breakelse:print("Incorrect, please try again")

This will loop eternally until the right answer is given, but you could easily adapt this to keep a count as well to give the user a fixed number of trials.