python异常中else的实例用法

while True:
    try:
        x = int(input('请输入X:'))
        y = int(input('请输入Y:'))
        value = x / y
        print('x/y is',value)
    except Exception as e:  # 发生异常时执行
        print('不正确的输入：', e)
        print('请重新输入')
    else:  # 未发生异常时执行
        break

def fetcher(obj, index):
    return obj[index]
 
x = 'spam'
 
try:
    print fetcher(x, 3)
except Exception:
    print 'hhh'
else:
    print 'has no exception'
    print fetcher(x, 2)
    print '---' * 10
 
try:
    print fetcher(x, 4)
except IndexError:
    print 'got exception'
else:
    print 'has no exception'
    print fetcher(x, 2)

m
has no exception
a
------------------------------
got exception