In python, if the user enters a string instead of number (integer value) then how can we show message to user that input is invalid? [duplicate]

Question

This question already has answers here:

Restrict inputs to only integer in python and display error message (2 answers)

How to protect my python code when a user inputs a string instead of an integer? (3 answers)

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var=int(input("Enter anything ==>"))
if(var%2==0): 
    print(var," is a Even number")
elif((var>="a" and var<="z") or (var>="A" and var<="Z")):
    print(var," is String")
    print("Enter a number to find it is even or odd")
else:
    print(var," is a Odd number")

OUTPUT

C:\Users\HP\OneDrive\Desktop\All Desktop apps\Python>python input.py
Enter an enter code everything ==>6
6 is a Even number

C:\Users\HP\OneDrive\Desktop\All Desktop apps\Python>python input.py
Enter anything ==>sdsd
Traceback (most recent call last):
File "C:\Users\HP\OneDrive\Desktop\All Desktop apps\Python\input.py", line 5, in var=int(input("Enter anything ==>"))
ValueError: invalid literal for int() with base 10: 'sdsd'

#if the user enters anything like any alphabet or special character, then how can we show msg to the user that the input is invalid or its an alphabet or a special character or an integer or about specific data type
==> var=int(input("Enter anything ==>"))
==> #var=input("Enter anything ==>")

Incorrect Code -->

Incorrect Output -->

Correct code using exception handling-->

Correct output-->

Please do not upload images of code/errors when asking a question. Include it as a formatted code block instead of an image. Please also ask a specific question! What's wrong with your code? Does it exit without doing anything? Does it do the wrong thing? Have you done any debugging? Please read How to Ask and the question checklist — pho
– pho, Commented Mar 22, 2022 at 15:29

Samwise · Accepted Answer · 2022-03-22 15:34:02Z

3

The simplest way is try/except:

var = input("Enter anything ==>")
try:
    if int(var) % 2:  
        print(f"{var} is an odd number")
    else:
        print(f"{var} is an even number")
except ValueError:
    print(f"{var} is not a number")

If you want to re-prompt the user when they enter something that's not a number, put the whole thing in a while loop and break it when they enter a valid number.

while True:
    var = input("Enter anything ==>")
    try:
        if int(var) % 2:  
            print(f"{var} is an odd number")
        else:
            print(f"{var} is an even number")
        break
    except ValueError:
        print(f"{var} is not a number")

edited Mar 22, 2022 at 15:34

answered Mar 22, 2022 at 15:29

Samwise

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In python, if the user enters a string instead of number (integer value) then how can we show message to user that input is invalid? [duplicate]

#if the user enters anything like any alphabet or special character, then how can we show msg to the user that the input is invalid or its an alphabet or a special character or an integer or about specific data type
==> var=int(input("Enter anything ==>"))
==> #var=input("Enter anything ==>")

Incorrect Code -->

Incorrect Output -->

Correct code using exception handling-->

Correct output-->

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Collectives™ on Stack Overflow

#if the user enters anything like any alphabet or special character, then how can we show msg to the user that the input is invalid or its an alphabet or a special character or an integer or about specific data type ==> var=int(input("Enter anything ==>")) ==> #var=input("Enter anything ==>")

Incorrect Code -->

Incorrect Output -->

Correct code using exception handling-->

Correct output-->

1 Answer 1

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#if the user enters anything like any alphabet or special character, then how can we show msg to the user that the input is invalid or its an alphabet or a special character or an integer or about specific data type
==> var=int(input("Enter anything ==>"))
==> #var=input("Enter anything ==>")