python异常处理

总结

• try中发生异常，执行except

• try中不发生异常，执行else

• try中的异常会阻止try接下来的所有操作

• try中的return会阻止else的执行

• 任何return都不会阻止finally的执行

def except_no_return():
    """
    try中发生异常，执行except
    输出：in try-in except-in finally-None
    :return: 
    """
    try:
        print('in try')
        a = 1/0
    except ZeroDivisionError:
        print('in except')
    else:
        print('in else')
    finally:
        # 返回这个
        print('in finally')


def else_no_return():
    """
    try中不发生异常，执行else
    输出：in try-in else-in finally-None
    :return: 
    """
    try:
        print('in try')
    except ZeroDivisionError:
        print('in except')
    else:
        print('in else')
    finally:
        # 返回这个
        print('in finally')


def try_except_finally():
    """
    try中的异常会阻止try接下来的所有操作
    输出：in try-in else-in finally-return in finally
    :return: 
    """
    try:
        print('in try')
        a = 1/0
        return "return in try"
    except ZeroDivisionError:
        print('in except')
        return "return in except"
    else:
        print('in else')
        return "return in else"
    finally:
        # 返回这个
        print('in finally')
        return "return in finally"


def try_finally():
    """
    try中的return会阻止else的执行
    输出：in try-in finally-return in finally
    :return: 
    """
    try:
        print('in try')
        return "return in try"
    except ZeroDivisionError:
        print('in except')
        return "return in except"
    else:
        print('in else')
        return "return in else"
    finally:
        # 返回这个
        print('in finally')
        return "return in finally"


def try_else_finally():
    """
    任何return都不会阻止finally的执行
    输出：in try-in else-in finally-return in finally
    :return: 
    """
    try:
        print('in try')
    except ZeroDivisionError:
        print('in except')
        return "return in except"
    else:
        print('in else')
        return "return in else"
    finally:
        # 返回这个
        print('in finally')
        return "return in finally"