Python 2.7仅数字作为输入，出现ValueError问题

Question

How do i stop python from giving me an ValueError everytime I put a letter in? Input must be a number! Using Python 2.7.3

Answer 1

Instead of using input() , use raw_input() , which returns a string.

input() is equivalent to eval(raw_input()) in Python 2.7. Hence, if you input a letter (let's say 'a' ), it will try look for a variable called 'a' . If there isn't one, a NameError is raised.

if you're working with numbers, then you can always call int() on the input received by using raw_input() . You could also use a try: except: structure to catch any ValueErrors incase the input is not a number.