初探异常

什么是异常与异常处理

  • 异常就是错误
  • 异常会导致程序崩溃并停止运行
  • 能监控并捕获异常，将异常部位的程序进行修理使得程序继续正常运行

异常的语法结构

try：
<代码块1> 被try关键字检查并保护的业务代码
except <异常的类型>:
<代码块2> # 代码块1 出现错误后执行的代码块
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捕获通用异常

  • 无法确定是哪种异常的情况下使用的捕获方法
try:
<代码块>
except Exception as e: # 单词首字母大写
<异常代码块>
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捕获具体异常

  • 确定是哪种异常的情况下使用的捕获方法
  • except <具体的异常类型>as e

捕获多个异常(1)

try:
print('try start')
res = 1/0
print('try finish')
except ZeroDivisionError as e:
print(e)
except Exception as e: #可以有多个except
print(‘this is a public excpet , bug is: %s' % e)
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  • 当except代码块有多个的时候，当捕获到第一个后，不会继续向下捕获

捕获多个异常(2)

try:
print('try start')
res = 1/0
print('try finish')
except (ZeroDivisionError, Exception) as e:
print(e)
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  • 当except代码后边的异常类型使用元组包裹起来，捕获到哪种抛出哪种

代码

# coding:utf-8
def upper(str_data):
new_str = 'None'
try:
new_str = str_data.upper()
except Exception as e:
print('程序出错了:{}'.format(e))
return new_str
result = upper(1)
print('result:', result)
def test():
try:
print('123')
1 / 0
print('hello')
except ZeroDivisionError as e:
print(e)
test()
def test1():
try:
print('hello')
print(name)
except (ZeroDivisionError, NameError) as e:
print(e)
print(type(e))
print(dir(e))
test1()
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