python 异常

1.处理异常
2.else 代码块

#异常
#ZeroDivisionError
try:
    print(5/0)
except ZeroDivisionError:
    print('you can not divide by zero')

print()
#FileNotFoundError
filename = 'alice.txt'
try:
    with open(filename,'r') as fobj:
        contents = fobj.read()
except FileNotFoundError:
    msg = 'sorry '+filename +' not found'
    print(msg)
print('give me two numbers and i will divide them')
print("enter  'q' to quit")

添加else代码块
while True:
    fnum = input('\nfirst num:')
    if fnum == 'q':
        break
    snum = input('\nsecond num:')
    try:
        answer = int(fnum)/int(snum)
    except:
        print('you can not divide by zero')
    else:
        print(answer)

输出控制台

image.png