Python cannot ignore str when input is int()-CodePudding

SO I have a program where the input is in an int, but when the user enters a str, the program crashes. I want the program to ignore any str that it can't convert to an int. I tried declaring a variable that said type(input). Then, I added an if statement:

if (variable) == str:
  print(oops)

Remember I declared the input as an int. So I don't know. Thank you.

CodePudding user response：

You can use exceptions for this. You get a Value Error when you try to convert a string input to int. By enclosing it in a try clause here, it is telling that if a Value Error arises, you can ignore it. For now I've used the pass statement, but if there's something else you want to do if the input is a string, you can add it there.

try:
    x = input()
    value = int(x)
    print(value)
except ValueError:
    pass

CodePudding user response：

You can use try-except to handle the case.

try:
    value = int(input())
except ValueError:
    print("Input is not an int type")
    pass

CodePudding user response：

In python you can call isinstance() on the variable passing the datatype you want to check for-

sent = 'your_string'
num = 24 
                                                                                      
isinstance(sent, int) # returns False
isinstance(num, int) # returns True 
isinstance(sent, str) # returns True 
isinstance(num, str) # returns False

Applicable with other data types too!

So a simple-

if not isinstance(str, int):
    print('Only integer values accepted')

CodePudding user response：

if my_input.isdigit():
    int(my_input)
    # your code goes here
else:
    print('oops')
    exit() # maybe you like to exit

CodePudding user response：

You could do something like

input_number = input("Enter your number")
if type(eval(input_number)) == int:
    #Do stuff
else:
    print('Sorry that is an invalid input')

I also noticed you said

Remeber I declared the input as an int

Python is not statically typed, so you don't have to declare a variable as a certain data type, and along with that even if you do, their type can still be changed.

CodePudding user response：

You can use str.isnumeric() to check if input is of int type or not. THis is better than using try..except

input_number = input("enter a number: ")
if input_number.isnumeric():
      input_number = int(input_number)
      # do magic