为什么此代码会产生缩进/语法错误

Question

I am trying to have the user enter an 8 digit barcode. If the code is not 8 digits long, it prints an error message. If it is 8 digits long, it raises an error.

def get_user_input():
    global total_price
    """ get input from user """
while len(str(GTIN))!=8:
    try:
        GTIN = int(input("input your gtin-8 number:"))
        if len(str(GTIN))!=8:
            print("make sure the length of the barcode is 8")
        else:
            print("make sure you enter a valid number")
        return GTIN

Answer 1

There actually several errors going on here:

1. Your indentation was being processed as the while loop being outside the function. Witespace in Python matters.
2. It is required to have an except with every try statement.
3. Additionally, GTIN was never initially defined, I fixed that.

Your new code:

def get_user_input():
    global total_price
    """ get input from user """
    GTIN = ""
    while True:
        try:
            GTIN = int(input("input your gtin-8 number:"))
            if len(str(GTIN)) == 8:
                break
            else:
                print("make sure the length of the barcode is 8")
        except:
            pass
    return GTIN
get_user_input()