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u2Python - best practive to raise @PYEXCEPTION... values

  • March 25, 2024
  • 3 replies
  • 0 views
Manu Fernandes
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hello,

I want to raise errors in my py scripts then these error catch by into @PYEXCEPTIONTYPE , @PYEXCEPTIONMSG, @PYEXCEPTIONTRACEBACK 

What can be the best method ? 

a/ to re-raise a error from a try sequence :

these sample can catch 3 types of error : path not found, json not correct, mykey not found ... 

def myfunc(path):
    result = ''
    try:
        f_path = open(path)
        config = json.load(f_path)
        a = config["mykey"]       
    except:
        raise

how can I have it at BASIC level into @PYEXCEPTIONTYPE , @PYEXCEPTIONMSG, @PYEXCEPTIONTRACEBACK  

in this case, @PYEXCEPTIONTYPE , @PYEXCEPTIONMSG, @PYEXCEPTIONTRACEBACK are null.

b/ to raise a error from script :

def myfnc(a)
     if a < 2:
          raise ValueError(f"integer above 1 expected, got {a}")

in this case, @PYEXCEPTIONTYPE , @PYEXCEPTIONMSG, @PYEXCEPTIONTRACEBACK are null.

Thanks

manu

    3 replies

    John Jenkins
    Forum|alt.badge.img+1
    • John Jenkins
    • Participating Frequently
    • 253 replies
    • March 26, 2024

    hello,

    I want to raise errors in my py scripts then these error catch by into @PYEXCEPTIONTYPE , @PYEXCEPTIONMSG, @PYEXCEPTIONTRACEBACK 

    What can be the best method ? 

    a/ to re-raise a error from a try sequence :

    these sample can catch 3 types of error : path not found, json not correct, mykey not found ... 

    def myfunc(path):
    result = ''
    try:
        f_path = open(path)
        config = json.load(f_path)
        a = config["mykey"]       
    except:
        raise

    how can I have it at BASIC level into @PYEXCEPTIONTYPE , @PYEXCEPTIONMSG, @PYEXCEPTIONTRACEBACK  

    in this case, @PYEXCEPTIONTYPE , @PYEXCEPTIONMSG, @PYEXCEPTIONTRACEBACK are null.

    b/ to raise a error from script :

    def myfnc(a)
     if a < 2:
          raise ValueError(f"integer above 1 expected, got {a}")

    in this case, @PYEXCEPTIONTYPE , @PYEXCEPTIONMSG, @PYEXCEPTIONTRACEBACK are null.

    Thanks

    manu

    Manu,

    I did some digging - does this work for you?

    def demo_catch():
    try:
        raise ValueError('This is ValueError')
        raise Exception('This is the exception')
    except Exception as error:
        print('Caught error: ' + repr(error))

>>> demo_catch()

    Regards

    JJ
    Mike Rajkowski
    Forum|alt.badge.img+1
    • Mike RajkowskiRocketeer
    • Rocketeer
    • 162 replies
    • March 27, 2024

    hello,

    I want to raise errors in my py scripts then these error catch by into @PYEXCEPTIONTYPE , @PYEXCEPTIONMSG, @PYEXCEPTIONTRACEBACK 

    What can be the best method ? 

    a/ to re-raise a error from a try sequence :

    these sample can catch 3 types of error : path not found, json not correct, mykey not found ... 

    def myfunc(path):
    result = ''
    try:
        f_path = open(path)
        config = json.load(f_path)
        a = config["mykey"]       
    except:
        raise

    how can I have it at BASIC level into @PYEXCEPTIONTYPE , @PYEXCEPTIONMSG, @PYEXCEPTIONTRACEBACK  

    in this case, @PYEXCEPTIONTYPE , @PYEXCEPTIONMSG, @PYEXCEPTIONTRACEBACK are null.

    b/ to raise a error from script :

    def myfnc(a)
     if a < 2:
          raise ValueError(f"integer above 1 expected, got {a}")

    in this case, @PYEXCEPTIONTYPE , @PYEXCEPTIONMSG, @PYEXCEPTIONTRACEBACK are null.

    Thanks

    manu

    Manu,

    I am wondering why you would expect anything when you raise an exception without defining what you raised, in the first example.

    The 2nd code segment would raise the exceptions and pass @PYEXCEPTIONTYPE , @PYEXCEPTIONMSG,  and @PYEXCEPTIONTRACEBACK

    forum.py

    -----

    def myfnc(a):
         if a < 2:
              raise ValueError(f"integer above 1 expected, got {a}")
         return a

    ------

    TEST

    ----

    ModuleName = "forum"
    FuncName = "myfnc"
    *            call the Python function
    CRT "Enter data ":;INPUT stuff
    IF NUM(stuff) THEN stuff += 0
    pyresults = PyCallFunction(ModuleName, FuncName, stuff)
     
    IF @PYEXCEPTIONTYPE = '' THEN
      CRT "OUTPUT = " :pyresults
    END ELSE
      CRT "    EXCEPTION TYPE:" :@PYEXCEPTIONTYPE
      CRT " EXCEPTION MESSAGE:" :@PYEXCEPTIONMSG
      CRT "EXCEPTIONTRACEBACK:" :@PYEXCEPTIONTRACEBACK
    END
     
    END
    -----
    Then when I run, I get:
    >RUN PBP TEST
    Enter data ?0
        EXCEPTION TYPE:ValueError
     EXCEPTION MESSAGE:integer above 1 expected, got 0
    EXCEPTIONTRACEBACK:Traceback (most recent call last):
     
      File "C:U2UVXDEMOPPforum.py", line 4, in myfnc
        raise ValueError(f"integer above 1 expected, got {a}")
     
    ValueError: integer above 1 expected, got 0
    So, I am not sure why you mentioned you received null?
    As for best practice, I would recommend you create your own custom exception, and raise that in your code.
    Following is a good site that shows how this can be done:
    https://www.programiz.com/python-programming/user-defined-exception#:~:text=In%20Python%2C%20we%20can%20define,pass%20try%3A%20...
    Mike
    Manu Fernandes
    Forum|alt.badge.img+2
    • Manu Fernandes
    • Author
    • Inspiring
    • 257 replies
    • March 28, 2024

    hello,

    I want to raise errors in my py scripts then these error catch by into @PYEXCEPTIONTYPE , @PYEXCEPTIONMSG, @PYEXCEPTIONTRACEBACK 

    What can be the best method ? 

    a/ to re-raise a error from a try sequence :

    these sample can catch 3 types of error : path not found, json not correct, mykey not found ... 

    def myfunc(path):
    result = ''
    try:
        f_path = open(path)
        config = json.load(f_path)
        a = config["mykey"]       
    except:
        raise

    how can I have it at BASIC level into @PYEXCEPTIONTYPE , @PYEXCEPTIONMSG, @PYEXCEPTIONTRACEBACK  

    in this case, @PYEXCEPTIONTYPE , @PYEXCEPTIONMSG, @PYEXCEPTIONTRACEBACK are null.

    b/ to raise a error from script :

    def myfnc(a)
     if a < 2:
          raise ValueError(f"integer above 1 expected, got {a}")

    in this case, @PYEXCEPTIONTYPE , @PYEXCEPTIONMSG, @PYEXCEPTIONTRACEBACK are null.

    Thanks

    manu

    Hi Mike, 

    In my sample, error can come from  : path not found, json not correct, mykey not found.

    Try: jump to except at first error. 

    If I place a 'raise' alone my script is supposed to re-raise the last error to the caller.

    I do not want to handle all potentialité errors into the py module, the calller (uvbasic) will do it.

    In my case, when except occurs uvbasic did not receive the @PYEXCEPTION, all are null.

    (the sample you provide first works correctly).

    Many thanks for your help. 

    Manu 


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