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?

Question

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:UsersHPOneDriveDesktopAll Desktop
appsPython>python input.py
Enter an enter code everything ==>6
6 is a Even
number

C:UsersHPOneDriveDesktopAll Desktop appsPython>python
input.py
Enter anything ==>sdsd
Traceback (most recent call
last):
File "C:UsersHPOneDriveDesktopAll Desktop
appsPythoninput.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–>

Asked By: Shubham-Misal

||

Source

Answer 1

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")

Answered By: Samwise

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?

Question:

#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–>

Answers:

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?

Question:

#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–>

Answers:

#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 ==>")