What is wrong with using a bare 'except'? [duplicate]












8
















This question already has an answer here:




  • About catching ANY exception

    8 answers




I tried making a function to check if an image is displayed on the screen using PyAutoGui and came up with this:



def check_image_on_screen(image):
try:
pyautogui.locateCenterOnScreen(image)
return True
except:
return False


And it works fine, but PyCharm tells me I shouldn't leave except bare. What is the problem with leaving it like this? Is there a more appropriate way of creating the same function?










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marked as duplicate by jamesdlin, Christian Dean python
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Mar 1 at 20:37


This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.














  • 1





    See also stackoverflow.com/q/4990718/20670

    – Tim Pietzcker
    Mar 1 at 16:25






  • 1





    Wikipedia has some good information on this--it's called error hiding.

    – John Szakmeister
    Mar 1 at 16:28











  • I'm not sure this is a duplicate of that. This is asking "Why not bare except" while that one is asking "How do I bare except." A good answer for the latter probably answers the former, but that doth not a duplicate make.

    – Adam Smith
    Mar 1 at 16:30
















8
















This question already has an answer here:




  • About catching ANY exception

    8 answers




I tried making a function to check if an image is displayed on the screen using PyAutoGui and came up with this:



def check_image_on_screen(image):
try:
pyautogui.locateCenterOnScreen(image)
return True
except:
return False


And it works fine, but PyCharm tells me I shouldn't leave except bare. What is the problem with leaving it like this? Is there a more appropriate way of creating the same function?










share|improve this question















marked as duplicate by jamesdlin, Christian Dean python
Users with the  python badge can single-handedly close python questions as duplicates and reopen them as needed.

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Mar 1 at 20:37


This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.














  • 1





    See also stackoverflow.com/q/4990718/20670

    – Tim Pietzcker
    Mar 1 at 16:25






  • 1





    Wikipedia has some good information on this--it's called error hiding.

    – John Szakmeister
    Mar 1 at 16:28











  • I'm not sure this is a duplicate of that. This is asking "Why not bare except" while that one is asking "How do I bare except." A good answer for the latter probably answers the former, but that doth not a duplicate make.

    – Adam Smith
    Mar 1 at 16:30














8












8








8









This question already has an answer here:




  • About catching ANY exception

    8 answers




I tried making a function to check if an image is displayed on the screen using PyAutoGui and came up with this:



def check_image_on_screen(image):
try:
pyautogui.locateCenterOnScreen(image)
return True
except:
return False


And it works fine, but PyCharm tells me I shouldn't leave except bare. What is the problem with leaving it like this? Is there a more appropriate way of creating the same function?










share|improve this question

















This question already has an answer here:




  • About catching ANY exception

    8 answers




I tried making a function to check if an image is displayed on the screen using PyAutoGui and came up with this:



def check_image_on_screen(image):
try:
pyautogui.locateCenterOnScreen(image)
return True
except:
return False


And it works fine, but PyCharm tells me I shouldn't leave except bare. What is the problem with leaving it like this? Is there a more appropriate way of creating the same function?





This question already has an answer here:




  • About catching ANY exception

    8 answers








python pyautogui except bare






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edited Mar 1 at 20:49









Peter Mortensen

13.7k1986113




13.7k1986113










asked Mar 1 at 16:20









CaioRamaglioCaioRamaglio

411




411




marked as duplicate by jamesdlin, Christian Dean python
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Mar 1 at 20:37


This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.









marked as duplicate by jamesdlin, Christian Dean python
Users with the  python badge can single-handedly close python questions as duplicates and reopen them as needed.

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Mar 1 at 20:37


This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.










  • 1





    See also stackoverflow.com/q/4990718/20670

    – Tim Pietzcker
    Mar 1 at 16:25






  • 1





    Wikipedia has some good information on this--it's called error hiding.

    – John Szakmeister
    Mar 1 at 16:28











  • I'm not sure this is a duplicate of that. This is asking "Why not bare except" while that one is asking "How do I bare except." A good answer for the latter probably answers the former, but that doth not a duplicate make.

    – Adam Smith
    Mar 1 at 16:30














  • 1





    See also stackoverflow.com/q/4990718/20670

    – Tim Pietzcker
    Mar 1 at 16:25






  • 1





    Wikipedia has some good information on this--it's called error hiding.

    – John Szakmeister
    Mar 1 at 16:28











  • I'm not sure this is a duplicate of that. This is asking "Why not bare except" while that one is asking "How do I bare except." A good answer for the latter probably answers the former, but that doth not a duplicate make.

    – Adam Smith
    Mar 1 at 16:30








1




1





See also stackoverflow.com/q/4990718/20670

– Tim Pietzcker
Mar 1 at 16:25





See also stackoverflow.com/q/4990718/20670

– Tim Pietzcker
Mar 1 at 16:25




1




1





Wikipedia has some good information on this--it's called error hiding.

– John Szakmeister
Mar 1 at 16:28





Wikipedia has some good information on this--it's called error hiding.

– John Szakmeister
Mar 1 at 16:28













I'm not sure this is a duplicate of that. This is asking "Why not bare except" while that one is asking "How do I bare except." A good answer for the latter probably answers the former, but that doth not a duplicate make.

– Adam Smith
Mar 1 at 16:30





I'm not sure this is a duplicate of that. This is asking "Why not bare except" while that one is asking "How do I bare except." A good answer for the latter probably answers the former, but that doth not a duplicate make.

– Adam Smith
Mar 1 at 16:30












2 Answers
2






active

oldest

votes


















15














Bare except will catch exceptions you almost certainly don't want to catch, including KeyboardInterrupt (the user hitting Ctrl+C) and Python-raised errors like SystemExit



If you don't have a specific exception you're expecting, at least except Exception, which is the base type for all "Regular" exceptions.





That being said: you use except blocks to recover from known failure states. An unknown failure state is usually irrecoverable, and it is proper behavior to fatally exit in those states, which is what the Python interpreter does naturally with an uncaught exception.



Catch everything you know how to handle, and let the rest propagate up the call stack to see if something else can handle it. In this case the error you're expecting (per the docs) is pyautogui.ImageNotFoundException






share|improve this answer































    1














    Basically, you're not taking advantage of the language to help you find problems. If you used except Exception as ex: you could do something like log the exception and know exactly what happened.






    share|improve this answer






























      2 Answers
      2






      active

      oldest

      votes








      2 Answers
      2






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes









      15














      Bare except will catch exceptions you almost certainly don't want to catch, including KeyboardInterrupt (the user hitting Ctrl+C) and Python-raised errors like SystemExit



      If you don't have a specific exception you're expecting, at least except Exception, which is the base type for all "Regular" exceptions.





      That being said: you use except blocks to recover from known failure states. An unknown failure state is usually irrecoverable, and it is proper behavior to fatally exit in those states, which is what the Python interpreter does naturally with an uncaught exception.



      Catch everything you know how to handle, and let the rest propagate up the call stack to see if something else can handle it. In this case the error you're expecting (per the docs) is pyautogui.ImageNotFoundException






      share|improve this answer




























        15














        Bare except will catch exceptions you almost certainly don't want to catch, including KeyboardInterrupt (the user hitting Ctrl+C) and Python-raised errors like SystemExit



        If you don't have a specific exception you're expecting, at least except Exception, which is the base type for all "Regular" exceptions.





        That being said: you use except blocks to recover from known failure states. An unknown failure state is usually irrecoverable, and it is proper behavior to fatally exit in those states, which is what the Python interpreter does naturally with an uncaught exception.



        Catch everything you know how to handle, and let the rest propagate up the call stack to see if something else can handle it. In this case the error you're expecting (per the docs) is pyautogui.ImageNotFoundException






        share|improve this answer


























          15












          15








          15







          Bare except will catch exceptions you almost certainly don't want to catch, including KeyboardInterrupt (the user hitting Ctrl+C) and Python-raised errors like SystemExit



          If you don't have a specific exception you're expecting, at least except Exception, which is the base type for all "Regular" exceptions.





          That being said: you use except blocks to recover from known failure states. An unknown failure state is usually irrecoverable, and it is proper behavior to fatally exit in those states, which is what the Python interpreter does naturally with an uncaught exception.



          Catch everything you know how to handle, and let the rest propagate up the call stack to see if something else can handle it. In this case the error you're expecting (per the docs) is pyautogui.ImageNotFoundException






          share|improve this answer













          Bare except will catch exceptions you almost certainly don't want to catch, including KeyboardInterrupt (the user hitting Ctrl+C) and Python-raised errors like SystemExit



          If you don't have a specific exception you're expecting, at least except Exception, which is the base type for all "Regular" exceptions.





          That being said: you use except blocks to recover from known failure states. An unknown failure state is usually irrecoverable, and it is proper behavior to fatally exit in those states, which is what the Python interpreter does naturally with an uncaught exception.



          Catch everything you know how to handle, and let the rest propagate up the call stack to see if something else can handle it. In this case the error you're expecting (per the docs) is pyautogui.ImageNotFoundException







          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Mar 1 at 16:23









          Adam SmithAdam Smith

          34.6k63276




          34.6k63276

























              1














              Basically, you're not taking advantage of the language to help you find problems. If you used except Exception as ex: you could do something like log the exception and know exactly what happened.






              share|improve this answer




























                1














                Basically, you're not taking advantage of the language to help you find problems. If you used except Exception as ex: you could do something like log the exception and know exactly what happened.






                share|improve this answer


























                  1












                  1








                  1







                  Basically, you're not taking advantage of the language to help you find problems. If you used except Exception as ex: you could do something like log the exception and know exactly what happened.






                  share|improve this answer













                  Basically, you're not taking advantage of the language to help you find problems. If you used except Exception as ex: you could do something like log the exception and know exactly what happened.







                  share|improve this answer












                  share|improve this answer



                  share|improve this answer










                  answered Mar 1 at 16:24









                  Charlie MartinCharlie Martin

                  91.9k18165242




                  91.9k18165242















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