Python Import Runtime Error
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a try statement with an except clause that mentions a particular class, that clause also handles any exception classes derived from that class (but python typeerror not exception classes from which it is derived). Two exception classes that are python filenotfounderror not related via subclassing are never equivalent, even if they have the same name. The built-in exceptions listed below python custom exception can be generated by the interpreter or built-in functions. Except where mentioned, they have an "associated value" indicating the detailed cause of the error. This may be a string or a python valueerror example tuple of several items of information (e.g., an error code and a string explaining the code). The associated value is usually passed as arguments to the exception class's constructor. User code can raise built-in exceptions. This can be used to test an exception handler or to report an error condition "just like" the situation in which the interpreter raises the same exception; but beware
Python Exception Message
that there is nothing to prevent user code from raising an inappropriate error. The built-in exception classes can be subclassed to define new exceptions; programmers are encouraged to derive new exceptions from the Exception class or one of its subclasses, and not from BaseException. More information on defining exceptions is available in the Python Tutorial under User-defined Exceptions. When raising (or re-raising) an exception in an except or finally clause __context__ is automatically set to the last exception caught; if the new exception is not handled the traceback that is eventually displayed will include the originating exception(s) and the final exception. When raising a new exception (rather than using a bare raise to re-raise the exception currently being handled), the implicit exception context can be supplemented with an explicit cause by using from with raise: raise new_exc from original_exc The expression following from must be an exception or None. It will be set as __cause__ on the raised exception. Setting __cause__ also implicitly sets the __suppress_context__ attribute to True, so that using raise learning the language. Here's a list of common errors that result in runtime error messages which will crash your program. 1) Forgetting to put a : at the end of an if, elif, else, for, while, class, or def statement. (Causes “SyntaxError: invalid syntax”) This error happens with code like this: python errno if spam == 42 print('Hello!') 2) Using = instead of ==. (Causes “SyntaxError: invalid syntax”) The = is the assignment operator python 3 exceptions while == is the "is equal to" comparison operator. This error happens with code like this: if spam = 42: print('Hello!') 3) Using the wrong amount of indentation. (Causes “IndentationError: unexpected indent” and “IndentationError: unindent does https://docs.python.org/3/library/exceptions.html not match any outer indentation level” and “IndentationError: expected an indented block”) Remember that the indentation only increases after a statement ending with a : colon, and afterwards must return to the previous indentation. This error happens with code like this: print('Hello!') print('Howdy!') ...and this: if spam == 42: print('Hello!') print('Howdy!') ...and this: if spam == 42: print('Hello!') 4) Forgetting the len() call in a for loop statement. (Causes “TypeError: 'list' object cannot http://inventwithpython.com/blog/2012/07/09/16-common-python-runtime-errors/ be interpreted as an integer”) Commonly you want to iterate over the indexes of items in a list or string, which requires calling the range() function. Just remember to pass the return value of len(someList), instead of passing just someList. This error happens with code like this: spam = ['cat', 'dog', 'mouse'] for i in range(spam): print(spam[i]) (Update: As a few have pointed out, what you might need is just for i in spam: rather than the above code. But the above is for the very legitimate case where you need the index in the body of the loop, rather than just the value itself.) 5) Trying to modify a string value. (Causes “TypeError: 'str' object does not support item assignment”) Strings are an immutable data type. This error happens with code like this: spam = 'I have a pet cat.' spam[13] = 'r' print(spam) What you probably want is this: spam = 'I have a pet cat.' spam = spam[:13] + 'r' + spam[14:] print(spam) 6) Trying to concatenate a non-string value to a string value. (Causes “TypeError: Can't convert 'int' object to str implicitly”) This error happens with code like this: numEggs = 12 print('I have ' + numEggs + ' eggs.') What you want to do is this: numEggs = 12 print('I have ' + str(numE here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss http://stackoverflow.com/questions/825909/catch-only-some-runtime-errors-in-python the workings and policies of this site About Us Learn more about Stack Overflow the company Business Learn more about hiring developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 6.2 million programmers, just like you, helping each python exception other. Join them; it only takes a minute: Sign up Catch only some runtime errors in Python up vote 5 down vote favorite I'm importing a module which raises the following error in some conditions: RuntimeError: pyparted requires root access I know that I can just check for root access before the import, but I'd like to know how python import runtime to catch this spesific kind of error via a try/except statement for future reference. Is there any way to differentiate between this RuntimeError and others that might be raised? python exception-handling try-catch runtime-error share|improve this question asked May 5 '09 at 17:01 lfaraone 10.9k143865 add a comment| 6 Answers 6 active oldest votes up vote 6 down vote accepted I know that I can just check for root access before the import, but I'd like to know how to catch this spesific kind of error via a try/except statement for future reference. Is there any way to differentiate between this RuntimeError and others that might be raised? If the error is caused by a specific condition, then I think the easiest way to catch the error is to test for the condition, and you can raise a more specific error yourself. After all the 'error' exists before the error is thrown, since in this case its a problem with the environment. I agree with those above - text matching on an error iPython Exception Class Methods