I am getting "Name undefined warning while compiling with try-catch block". Please give some idea about this error.
NAME UNDEFINED ERROR IMAGE
# Importing random package
import random
try:
top_range = int(input("Enter the range:"))
except ValueError:
print("Please enter he Integer Number")
# Getting the random number from system
sys_guess = random.randint(0, top_range)
print("System Guess =", sys_guess)
print("Try to GUESS the Number within 3 entries, MAXIMUM 3 guess......!")
# making for increment
guess = 0
# Guessing the number
while sys_guess >= 0:
user_input = int(input("Enter guessed number: "))
if sys_guess != user_input:
# incrementing the wrong value
guess += 1
print("Wrong Guess-->")
if guess == 2:
print("you have only one guess left")
if guess > 2:
print("Maximum number of guess tried, Failed to obtain the guess!!!!!")
break
else:
# incrementing the correct value
guess += 1
print("!HURRAY***CORRECT GUESS***!")
if sys_guess == user_input:
break
# printing the total number of guess
print("Total Guesses=", guess)
Stick the try catch block in a loop that will continue endlessly until the user enters a valid number. If there is an exception at the moment the top_range value is never defined thus the error.
while True:
try:
top_range = int(input("Enter the range:"))
break
except ValueError:
print("Please enter he Integer Number")
Related
while True:
try:
num = int(input("Enter a number [n>2]: "))
if num <= 2:
raise ValueError
break
except ValueError:
print("Not a number. Try again!")
continue
Is it normal that VSCode is giving me an "undefined variable" on num after asking for user input? I mean, num will be defined when the user enters a number.
It is happening because the VS code debug AI is warning you if you use the num variable in the except block, or somewhere else in the code, it will cause an error. To solve it, you can do this
num = 0
while True:
try:
num = int(input("Enter a number [n>2]: "))
if num <= 2:
raise ValueError
break
except ValueError:
print("Not a number. Try again!")
continue
And it should go away since I have defined the variable num to work in all scenarios
I'm processing integer inputs from a user and would like for the user to signal that they are done with inputs by typing in 'q' to show they are completed with their inputs.
Here's my code so far:
(Still very much a beginner so don't flame me too much)
def main():
print("Please enter some numbers. Type 'q' to quit.")
count = 0
total = 0
num=[]
num = int(input("Enter a number: "))
while num != "q":
num = int(input("Enter a number: "))
count += 1
total += num
del record[-1]
print (num)
print("The average of the numbers is", total / count)
main()
Any feedback is helpful!
You probably get a ValueError when you run that code. That's python's way of telling you that you've fed a value into a function that can't handle that type of value.
Check the Exceptions docs for more details.
In this case, you're trying to feed the letter "q" into a function that is expecting int() on line 6. Think of int() as a machine that only handles integers. You just tried to stick a letter into a machine that's not equipped to handle letters and instead of bursting into flames, it's rejecting your input and putting on the breaks.
You'll probably want to wrap your conversion from str to int in a try: statement to handle the exception.
def main():
num = None
while num != "q":
num = input("Enter number: ")
# try handles exceptions and does something with them
try:
num = int(num)
# if an exception of "ValueError" happens, print out a warning and keep going
except ValueError as e:
print(f'that was not a number: {e}')
pass
# if num looks like an integer
if isinstance (num, (int, float)):
print('got a number')
Test:
Enter number: 1
got a number
Enter number: 2
got a number
Enter number: alligator
that was not a number: invalid literal for int() with base 10: 'alligator'
Enter number: -10
got a number
Enter number: 45
got a number
Enter number: 6.0222
that was not a number: invalid literal for int() with base 10: '6.0222'
I'll leave it to you to figure out why 6.02222 "was not a number."
changing your code as little as possible, you should have...
def main():
print("Please enter some numbers. Type 'q' to quit.")
count = 0
total = 0
num=[]
num.append(input("Enter a number: "))
while num[-1] != "q":
num.append(input("Enter a number: "))
count += 1
try:
total += int(num[-1])
except ValueError as e:
print('input not an integer')
break
print (num)
print("The average of the numbers is", total / count)
main()
You may attempt it the way:
def main():
num_list = [] #list for holding in user inputs
while True:
my_num = input("Please enter some numbers. Type 'q' to quit.")
if my_num != 'q':
num_list.append(int(my_num)) #add user input as integer to holding list as long as it is not 'q'
else: #if user enters 'q'
print(f'The Average of {num_list} is {sum(num_list)/len(num_list)}') #calculate the average of entered numbers by divide the sum of all list elements by the length of list and display the result
break #terminate loop
main()
This is my first post in this community and I am a beginner of course. I look forward to the day I can help others out. Anyway, this is the a simple code and I would like it so that there is an error if the user enters a string. Unfortunately, it does not execute the way I'd like to, here's the code:
number = 1
guess = int(input('Guess this number: '))
while True:
try:
if guess > number:
print("Number is too high, go lower, try again")
guess = int(input('Guess this number: '))
elif guess < number:
print("Too low, go higher, try again")
guess = int(input('Guess this number: '))
else:
print("That is correct")
break
except (SyntaxError, ValueError):
print("You can only enetr numbers, try again")
When the program gets executed, and it asks me to "Guess this number: ", when I write any string e.g. "d", it gives the error:
Guess this number: d
Traceback (most recent call last):
File "Numberguess.py", line 5, in <module>
guess = int(input('Guess this number: '))
ValueError: invalid literal for int() with base 10: 'd'
Thank you for your time and support.
Welcome to Stack Overflow! Everyone needs to start somewhere
Take a look at the code below:
# import random to generate a random number within a range
from random import randrange
def main():
low = 1
high = 100
# gen rand number
number = gen_number(low, high)
# get initial user input
guess = get_input()
# if user did not guess correct than keep asking them to guess
while guess != number:
if guess > number:
print("You guessed too high!")
guess = get_input()
if guess < number:
print("You guess too low!")
guess = get_input()
# let the user know they guess correct
print(f"You guessed {guess} and are correct!")
def gen_number(low, high):
return randrange(low, high)
# function to get input from user
def get_input():
guess = input(f"Guess a number (q to quit): ")
if guess == 'q':
exit()
# check to make sure user input is a number otherwise ask the user to guess again
try:
guess = int(guess)
except ValueError:
print("Not a valid number")
get_input()
# return guess if it is a valid number
return guess
# Main program
if __name__ == '__main__':
main()
This was a great opportunity to include Python's random module to generate a random number within a range. There is also a nice example of recursion to keep asking the user to guess until they provide valid input. Please mark this answer as correct if this works and feel free to leave comments if you have any questions.
Happy Coding!!!
Take a look at this line:
guess = int(input('Guess this number: '))
You try to convert string to int, it's possible, but only if the string represents a number.
That's why you got the error.
The except didn't worked for you, because you get the input for the variable out of "try".
By the way, there is no reason to input in the if, so your code should look like this:
number = 1
while True:
try:
guess = int(input('Guess this number: '))
if guess > number:
print("Number is too high, go lower, try again")
elif guess < number:
print("Too low, go higher, try again")
else:
print("That is correct")
break
except (SyntaxError, ValueError):
print("You can only enetr numbers, try again")
I would just use .isdigit(). The string would be validated at that point and then you would turn it into an int if validation works.
guess = input('Guess this number: ')
if guess.isdigit():
guess = int(guess)
else:
print("You can only enter numbers, try again")
Also worth to mention that try/excepts are cool and they get the job done, but it's a good habit to try to reduce them to zero, instead of catching errors, validate data beforehand.
The next example would do it:
number = 1
while True:
# Step 1, validate the user choice
guess = input('Guess this number: ')
if guess.isdigit():
guess = int(guess)
else:
print("You can only enter numbers, try again")
continue
# Step 2, play the guess game
if guess > number:
print("Number is too high, go lower, try again")
elif guess < number:
print("Too low, go higher, try again")
else:
print("That is correct")
break
the problem is in the first line. when you convert the input from the user directly to int, when a user inputs a letter, the letter cannot be converted to int, which causes the error message you get.
to solve this you need to do
guess = input('Guess this number: ')
if not guess.isdigit():
raise ValueError("input must be of type int")
Python just keeps repeating back to me "How many random numbers do you want?" and won't move on to the next input.
I've tried most things I could think of.
do_program = True
while(do_program):
while(True):
try:
number_of_numbers = float(input("How many random numbers do you want?"))
if(number_of_numbers < 0):
print("Negative numbers are not allowed.")
continue
except ValueError:
print("The value you entered is invalid. Please enter numerial values only.")
else:
break
while(True):
try:
lowest_number = float(input("What is the lowest random number you want?"))
if(lowest_number < 0):
print("Negative numbers are not allowed.")
continue
except ValueError:
print("The value you entered is invalid. Please enter numerial values only.")
else:
break
while(True):
try:
highest_number = float(input("What is the highest random number you want?"))
if(highest < 0):
print("Negative numbers are not allowed.")
continue
except ValueError:
print("The value you entered is invalid. Please enter numerial values only.")
else:
break
import random
print("The numbers were written to randomnum.txt.")
def main():
for count in range(number_of_numbers):
number = random.randint(lowest_number, highest_number)
print(number)
main()
Right now I just want to focus on getting to my second and third input statements.
After successfully reading number_of_numbers the code breaks out of the inner while(True) loop and then resumes the outer while(do_program) loop. This causes the same code to be executed over and over. Perhaps rework your code to process the input before returning to the main loop?
Below is my code for guessing a random number. I had to check the input to make sure it was an integer and within the 1-20 range. Everything is working. It outputs the right response if it is not an integer or is out of range but then it continues through the while loop. I thought the try except would send it back before it continued. What have I done incorrectly here? I cannot figure out the problem. Thank you for any help!
import random
tries = 0
name=(raw_input('Hello! What is your name? '))
number = random.randint(1, 20)
print('Hello, ' + name + ', I am thinking of a number between 1 and 20.')
while tries < 6:
guess = (raw_input('Take a guess.' ))
try:
guess = int(guess)
except ValueError:
print 'You did not enter a valid number, try again.'
tries = tries + 1
if guess<1 or guess>20:
print 'Your guess is not between 1 and 20'
if guess < number:
print 'Your guess is too low.'
if guess > number:
print 'Your guess is too high.'
if guess == number:
break
if guess == number:
print 'Good job, ',name,'! You guessed my number in ',tries,' guesses!'
if guess != number:
print 'Sorry, The number I was thinking of was ',number
All you do is when a ValueError is raised is to have an extra line printed. If you want your loop to start from the beginning, add continue in the except block. If you want to count invalid inputs as tries, move the line where you increment tries to the beginning of your loop.
tries += 1 # increment tries here if invalid inputs should count as a try, too
# increment tries after the except block if only valid inputs should count as a try
# get input here
try:
guess = int(guess)
except ValueError:
# inform user that the input was invalid here
continue # don't execute the rest of the loop, start with the next loop
You can either put another continue where you check whether the number is too high or too low:
if guess<1 or guess>20:
print 'Your guess is not between 1 and 20'
continue
or use an if/elif construct:
if guess<1 or guess>20:
print 'Your guess is not between 1 and 20'
elif guess < number:
print 'Your guess is too low.'
elif guess > number:
print 'Your guess is too high.'
else: # guess == number
break
I recommend the if/elif. Having multiple continues in a loop can make it hard to follow.
You told it to print something, but Python doesn't know that you don't want it to do other things during that iteration. Sometimes you might want it to go on only if there was an error. To say "skip this loop", use continue:
try:
guess = int(guess)
except ValueError:
print 'You did not enter a valid number, try again.'
continue
You need to continue after both tests and only increment the tries once you have successfully passed the tests.
import random
tries = 0
name=(raw_input('Hello! What is your name? '))
number = random.randint(1, 20)
print('Hello, ' + name + ', I am thinking of a number between 1 and 20.')
while tries < 6:
guess = (raw_input('Take a guess.' ))
try:
guess = int(guess)
except ValueError:
print 'You did not enter a valid number, try again.'
continue
if guess<1 or guess>20:
print 'Your guess is not between 1 and 20'
continue
tries = tries + 1
if guess < number:
print 'Your guess is too low.'
if guess > number:
print 'Your guess is too high.'
if guess == number:
break
if guess == number:
print 'Good job, ',name,'! You guessed my number in ',tries,' guesses!'
if guess != number:
print 'Sorry, The number I was thinking of was ',number