Catch any error in Python

Question

Is it possible to catch any error in Python? I don't care what the specific exceptions will be, because all of them will have the same fallback.

Solution 1

Using except by itself will catch any exception short of a segfault.

try:
    something()
except:
    fallback()

You might want to handle KeyboardInterrupt separately in case you need to use it to exit your script:

try:
    something()
except KeyboardInterrupt:
    return
except:
    fallback()

There's a nice list of basic exceptions you can catch here. I also quite like the traceback module for retrieving a call stack from the exception. Try traceback.format_exc() or traceback.print_exc() in an exception handler.

Solution 2

try:
    # do something
except Exception, e:
    # handle it

For Python 3.x:

try:
    # do something
except Exception as e:
    # handle it

Solution 3

You might want also to look at sys.excepthook:

When an exception is raised and uncaught, the interpreter calls sys.excepthook with three arguments, the exception class, exception instance, and a traceback object. In an interactive session this happens just before control is returned to the prompt; in a Python program this happens just before the program exits. The handling of such top-level exceptions can be customized by assigning another three-argument function to sys.excepthook.

Example:

def except_hook(type, value, tback):
    # manage unhandled exception here
    sys.__excepthook__(type, value, tback) # then call the default handler

sys.excepthook = except_hook

Solution 4

Quoting the bounty text:

I want to be able to capture ANY exception even weird ones like keyboard interrupt or even system exit (e.g. if my HPC manger throws an error) and get a handle to the exception object e, whatever it might be. I want to process e and custom print it or even send it by email

Look at the exception hierarchy, you need to catch BaseException:

BaseException
 +-- SystemExit
 +-- KeyboardInterrupt
 +-- GeneratorExit
 +-- Exception

This will capture KeyboardInterrupt, SystemExit, and GeneratorExit, which all inherit from BaseException but not from Exception, e.g.

try:
    raise SystemExit
except BaseException as e:
    print(e.with_traceback)

Solution 5

Not mentioning the type of exception you want to handle itself does the job.

try this:

    try:
       #code in which you expect an exception 
    except:
       #prints the exception occured

if you want to know the type of exception occurred:

    try:
       #code in which you expect an exception 
    except Exception as e:
       print(e)
       #for any exception to be catched

for detailed explanation go trough this https://www.tutorialspoint.com/python/python_exceptions.htm

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