Error Exception In Python
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Python Error Exception Message
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Python Exception Error Line Number
be covered in this tutorial. Here is a list standard Exceptions available in Python: Standard Exceptions. Assertions: This would be covered in Assertions in Python tutorial. List of Standard Exceptions − EXCEPTION NAME DESCRIPTION Exception Base class for all exceptions StopIteration Raised when the next() method of an iterator does not point to any object. SystemExit Raised by the sys.exit() function. StandardError Base class for all built-in exceptions except StopIteration and SystemExit. ArithmeticError Base class for all errors that occur for numeric calculation. OverflowError Raised when a calculation exceeds maximum limit for a numeric type. FloatingPointError Raised when a floating point calculation fails. ZeroDivisonError Raised when division or modulo by zero takes place for all numeric types. AssertionError Raised in case of failure of the Assert statement. AttributeError Raised in case of failure of attribute reference or assignment. EOFError Raised when there is no input from either the raw_input() or input() function and the end of file is reached. ImportError Raised when an import statement fails. KeyboardInterrupt Raised when the user interrupts program execution, usually by pressing Ctrl+c. LookupError Base class for all lookup errors. IndexErrorKeyError Raised when an index is not found in a sequence.Raised when the specified key
Pages Local Site Map ------------------------ Rename Page Delete Page ------------------------ ------------------------ Remove Spam Revert to this revision ------------------------ SlideShow User Login Handling Exceptions The simplest way to handle exceptions is with a "try-except" block: 1 (x,y) = exception class python (5,0) 2 try: 3 z = x/y 4 except ZeroDivisionError: exception python 3 5 print "divide by zero" If you wanted to examine the exception from code, you could have:
Print Exception Python
1 (x,y) = (5,0) 2 try: 3 z = x/y 4 except ZeroDivisionError as e: 5 z = e # representation: " Error: %s
here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site About Us Learn more about Stack Overflow the http://stackoverflow.com/questions/2052390/manually-raising-throwing-an-exception-in-python 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 4.7 http://www.pythonforbeginners.com/error-handling/python-try-and-except million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up Manually raising (throwing) an exception in Python up vote 785 down vote favorite 185 How can I raise an python exception exception in Python so that it can later be caught via an except block? python exception exception-handling share|improve this question edited Feb 3 '15 at 14:37 DavidRR 5,16472747 asked Jan 12 '10 at 21:07 TIMEX 40.6k197519823 add a comment| 3 Answers 3 active oldest votes up vote 766 down vote accepted How do I manually throw/raise an exception in Python? Use the most specific Exception constructor that semantically fits your issue. Be specific python exception error in your message, e.g.: raise ValueError('A very specific bad thing happened') Don't do this: Avoid raising a generic Exception, to catch it, you'll have to catch all other more specific exceptions that subclass it. Hiding bugs raise Exception('I know Python!') # don't, if you catch, likely to hide bugs. For example: def demo_bad_catch(): try: raise ValueError('represents a hidden bug, do not catch this') raise Exception('This is the exception you expect to handle') except Exception as error: print('caught this error: ' + repr(error)) >>> demo_bad_catch() caught this error: ValueError('represents a hidden bug, do not catch this',) Won't catch and more specific catches won't catch the general exception: def demo_no_catch(): try: raise Exception('general exceptions not caught by specific handling') except ValueError as e: print('we will not catch e') >>> demo_no_catch() Traceback (most recent call last): File "
how to handle those. Exception handling allows us to continue our program (or terminate it) if an exception occurs. Error Handling Error handling in Python is done through the use of exceptions that are caught in try blocks and handled in except blocks. Try and Except If an error is encountered, a try block code execution is stopped and transferred down to the except block. In addition to using an except block after the try block, you can also use the finally block. The code in the finally block will be executed regardless of whether an exception occurs. Raising an Exception You can raise an exception in your own program by using the raise exception [, value] statement. Raising an exception breaks current code execution and returns the exception back until it is handled. Example A try block look like below try: print "Hello World" except: print "This is an error message!" Exception Errors Some of the common exception errors are: IOError If the file cannot be opened. ImportError If python cannot find the module ValueError Raised when a built-in operation or function receives an argument that has the right type but an inappropriate value KeyboardInterrupt Raised when the user hits the interrupt key (normally Control-C or Delete) EOFError Raised when one of the built-in functions (input() or raw_input()) hits an end-of-file condition (EOF) without reading any data Example Let's have a look at some examples using exceptions. except IOError: print('An error occured trying to read the file.') except ValueError: print('Non-numeric data found in the file.') except ImportError: print "NO module found" except EOFError: print('Why did you do an EOF on me?') except KeyboardInterrupt: print('You cancelled the operation.') except: print('An error occured.') There are a number of built-in exceptions in Python. Recommended Python Training – Treehouse For Python training, our top recommendation is Treehouse. Treehouse is an online training service that teaches web design, web development and app deve