如下所示:
def test1():  try:   print('to do stuff')   raise Exception('hehe')   print('to return in try')   return 'try' except Exception:   print('process except')   print('to return in except')   return 'except' finally:   print('to return in finally')   return 'finally'test1Return = test1()print('test1Return : ' + test1Return)輸出:
to do stuffprocess exceptto return in exceptto return in finallytest1Return : finally
在 try 中 raise一個異常,就立刻轉入 except 中執行,在except 中遇到 return 時,就強制轉到 finally 中執行, 在 finally 中遇到 return 時就返回
def test2():  try:   print('to do stuff')   print('to return in try')   return 'try' except Exception:   print('process except')   print('to return in except')   return 'except' finally:   print('to return in finally')   return 'finally'test2Return = test2()print('test1Return : ' + test2Return)輸出:
to do stuffto return in tryto return in finallytest2Return : finally
這里在 try 中沒有拋出異常,因此不會轉到 except 中,但是在try 中遇到return時,也會立即強制轉到finally中執行,并在finally中返回
test1和test2得到的結論:
無論是在try還是在except中,遇到return時,只要設定了finally語句,就會中斷當前的return語句,跳轉到finally中執行,如果finally中遇到return語句,就直接返回,不再跳轉回try/excpet中被中斷的return語句
def test3():  i = 0 try:   i += 1 print('i in try : %s'%i)   raise Exception('hehe') except Exception:   i += 1 print('i in except : %s'%i)   return i   finally:   i += 1 print ('i in finally : %s'%i )print('test3Return : %s'% test3())輸出:
i in try : 1i in except : 2i in finally : 3test3Return : 2def test4():  i = 0 try:   i += 1 return i  finally:   i += 1 print ('i in finally : %s'%i )print('test4Return : %s' % test4())輸出
i in finally : 2test4Return : 1
test3和test4得到的結論:
在except和try中遇到return時,會鎖定return的值,然后跳轉到finally中,如果finally中沒有return語句,則finally執行完畢之后仍返回原return點,將之前鎖定的值返回(即finally中的動作不影響返回值),如果finally中有return語句,則執行finally中的return語句。
def test5():  for i in range(5):   try:     print('do stuff %s'%i)     raise Exception(i)   except Exception:     print('exception %s'%i)     continue finally:     print('do finally %s'%i)test5()輸出
do stuff 0exception 0do finally 0do stuff 1exception 1do finally 1do stuff 2exception 2do finally 2do stuff 3exception 3do finally 3do stuff 4exception 4do finally 4
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