python - Ignore print statements when try catch exception

Question

I have this simple try-except code:

self.tf.router.EchoProg(state=1)
try:
    print "\tCheckTestFirmwareCommunication_SetPort: "  
    print self.tf.DUT.CheckTestFirmwareCommunication_SetPort()
except NoResponseException, e:
    print "\tCheckTestFirmwareCommunication_SetPort: ", repr(e)
self.tf.router.EchoProg(state=0)

Output with Exception:

CheckTestFirmwareCommunication_SetPort:
CheckTestFirmwareCommunication_SetPort: DD_NoResponseException()

Questions:

1. Can someone explain why i still see the print statements even if i get an exception?

2. Is it possible to ignore print statements if the try-except catch an exception?

Answer 1

引发异常的是第二 print行：

print self.tf.DUT.CheckTestFirmwareCommunication_SetPort()

第一print行没有并被执行。

Python 执行try套件中的每条语句，并且只有在抛出异常时，才会中止执行并转移到except块中。如果您不希望在引发异常print时执行第一条语句，请先调用该方法：CheckTestFirmwareCommunication_SetPort

self.tf.router.EchoProg(state=1)
try:
    port = self.tf.DUT.CheckTestFirmwareCommunication_SetPort()
    print "\tCheckTestFirmwareCommunication_SetPort: "  
    print port
except NoResponseException, e:
    print "\tCheckTestFirmwareCommunication_SetPort: ", repr(e)
self.tf.router.EchoProg(state=0)

Answer 2

第一条print语句在异常发生之前执行，因此它们被打印出来。

这里的异常由self.tf.DUT.CheckTestFirmwareCommunication_SetPort(). 您可以将打印语句移到它下面，以便在第一行成功执行时打印它。

try:
    print self.tf.DUT.CheckTestFirmwareCommunication_SetPort()
    print "\tCheckTestFirmwareCommunication_SetPort: "  
except NoResponseException, e:
    print "\tCheckTestFirmwareCommunication_SetPort: ", repr(e)

Answer 3

问题是该行引发了异常：

print self.tf.DUT.CheckTestFirmwareCommunication_SetPort()

所以这一行：

print "\tCheckTestFirmwareCommunication_SetPort: "  

总是会被执行。

以避免将您的代码更改为：

self.tf.router.EchoProg(state=1)
try:

    port =  self.tf.DUT.CheckTestFirmwareCommunication_SetPort()
except NoResponseException, e:
    print "\tCheckTestFirmwareCommunication_SetPort: ", repr(e)
else:
    print "\tCheckTestFirmwareCommunication_SetPort: ", port  
self.tf.router.EchoProg(state=0)