Using regular expression to validate user input is an integer

Question

I am trying to validate a user's input. I only want the user to be able to enter a positive or negative integer. All other inputs (i.e. anything with letters) should be rejected

I have the code below at the minute, however I am getting an error. I'm assuming it has to do with the data types but am unsure how to fix this.

import re

number =input("Please enter a number: ")
number=int(number)
while not re.match("^[0-9 \-]+$", number):
    print ("Error! Make sure you only use numbers")
    number = input("Please enter a number: ")
print("You picked number "+ number)

Answer 1

If all you care about is that the input was a valid numeric literal, don't even bother with the regexp. int will correctly parse the string or raise an exception.

while True:
    s = input("Please enter a number: ")
    try:
        n = int(s)
        break
    except ValueError:
        print("Error! Make sure you only use numbers")
print("You picked number " + n)