try-except-else-finally

def test(a):
    try:
        print(‘this is try...‘)
        if a == 0:
            raise ZeroDivisionError(‘customize erro‘)
        # 如果try有return则不再执行else的代码
        return str(10/a)
    # 多个except之间是互斥关系
    except BaseException as e:
        print(‘this is except 1...‘ + str(e))
        return ‘except 1‘
    except ZeroDivisionError as e:
        print(‘this is except 2...‘ + str(e))
        return ‘except 2‘
    #
    else:
        print(‘this is else...‘)
        return (‘else‘)
    finally:
        # finally中的代码，无论什么情况都要执行，即使之前有return！
        print(‘this is finally...即使有return也要先执行finally之后再执行return！‘)
        # 如果finally中有return会覆盖之前的return，如果finally中没有则用之前的return
        return ‘finally‘


print(‘the result is: ‘+str(test(0)))