Python：获取列表索引超出范围错误

Question

Getting list index out of range error in line amount=int(values 1 ),as far as I can see ,I am not violating any index ranges. I have checked these
Python error - list index out of range?
List index out of range?
list index out of range
but they are of not much use.

netAmount = 0
while True:
    s = raw_input()
    if not s:
        break
    values = s.split(" ")
    operation = values[0]
    amount = int(values[1])  
    if operation=="D":
        netAmount+=amount
    elif operation=="W":
        netAmount-=amount
    else:
        pass

print netAmount

**edited-After printing after the split method print is working fine but error still persists

Answer 1

You must add the test before the split to avoid accessing the list out of range:

netAmount = 0
while True:
    s = raw_input()
    if not s or s=="0":
        break
    values = s.split(" ")
    operation = values[0]
    amount = int(values[1])
    if operation=="D":
        netAmount+=amount
    elif operation=="W":
        netAmount-=amount
    else:
        pass

print netAmount