Python try except异常捕获机制原理解析

aa = [1,2,4,5,7,0,2]
for ii in aa:
  try:
    h = 2/ii
    print(h)
  except:  #发生异常时备用
    h = 2/(ii+1)
    print(h)

dict_ = {}
try:
  print(dict_['test'])
  print(' --- testing... --- ')
except KeyError as e:
  print('--- the error is ---:', e)  #单个异常
print(' ---finished!!--- ')

num = [9,7,0,1,4,'16']
for x in num:
  try: 
    print (1/x)
  except ZeroDivisionError:
    print('error：0做除数！')
  except TypeError: # 当报错信息为TypeError，执行下面的语句。
    print('error：数值类型错误！')
print(' ---finished!!--- ')

num = [9,7,0,1,4,'16']
for x in num:
  try: 
    print (1/x)
  except ZeroDivisionError:
    print('error：0做除数！')  #特定异常和Exception混合使用
  except Exception as e:
    print('the Exception is:',e)
print(' ---finished!!--- ')

dict_ = {'test':'这个地方是哪里？'}
try:
  print(dict_['test'])
  print(' --- testing... --- ')
except KeyError as e:
  print('--- the error is ---:', e)  #单个异常
else:
  print('没有发生异常！')
print(' ---finished!!--- ')

dict_ = {'test':'这个地方是哪里？'}
try:
  print(dict_['test'])
  print(' --- testing... --- ')
except KeyError as e:
  print('--- the error is ---:', e)  #单个异常
else:
  print('没有发生异常！')
finally:
  print('总可以被执行的语句。。。')
print(' ---finished!!--- ')