异常中的finally

  • finally的功能和用法

功能

  • 无论是否发生异常 ， 一定会执行的代码块
  • 在函数中， 即便在try或except中进行了return也依然会执行finally语法块
  • try语法至少要伴随except或finally中的一个

用法

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try:
    <代码块1>
except:
    <代码块2>
finally:
    <代码块3>

历史

  • 在python 2.5 之前的版本， finally需要独立使用，不可以和try配合，之后才演变成现在的模式

代码

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# coding:utf-8

def test1():
    try:
        1 / 0
    except Exception as e:
        print(e)
    finally:
        return 'finally'


result = test1()
print(result)


def test2():
    try:
        1 / 0
    except Exception as e:
        print('111')
        return e
    finally:
        print('finally')


print('-------')
result = test2()
print(result)


def test3():
    try:
        print('try test 11')
        return 'try'
    except Exception as e:
        print('e')
    finally:
        print('finally test')


print('------')
result = test3()
print(result)


def test4():
    try:
        1 / 0
    except Exception as e:
        print('1')
        return e
    finally:
        print('2')
        return 'finally'


print('----------')
result = test4()
print(result)


def test5():
    try:
        print('1try')
        return 'try'
    except Exception as e:
        print('e')
    finally:
        print('2finally')
        return 'finally'


print('========')
result = test5()
print(result)


def test6():
    try:
        print('try1')
        1 / 0
        print('try3')
    finally:
        # print('i am finally')
        return 'i am finally'


print('-------')
result = test6()
print(result)