Exception in python unknown errors

Question

 except ValueError:
 print "the input is Invaild(dd.mm.year)"
 except as e:
 print "Unknown error"
 print e

This is the code I wrote, if an error different then valueerror will happen will it print it in e? thanks

Answer 1

You'll need to catch the BaseException or object here to be able to assign to e:

except ValueError:
 print "the input is Invaild(dd.mm.year)"
except BaseException as e:
 print "Unknown error"
 print e

or, better still, Exception:

except ValueError:
 print "the input is Invaild(dd.mm.year)"
except Exception as e:
 print "Unknown error"
 print e

The blanket except: will catch the same exceptions as BaseException, catching just Exception will ignore KeyboardInterrupt, SystemExit, and GeneratorExit. Not catching these there is generally a good idea.

For details, see the exceptions documentation.

• SethMMorton: Does Exception also ignore SyntaxError?
• Martijn Pieters: @SethMMorton: No, SyntaxError is a subclass of Exception.
• SethMMorton: Interesting... It seems odd to me that it would be a subclass of Exception, because in general I wouldn't want to catch a syntax error in a try statement.
• Martijn Pieters: @SethMMorton: During compilation the try doesn't apply yet. Only when you use import, eval, exec or compile() can you catch SyntaxError exceptions.
• SethMMorton: When I see that written in front of me it makes total sense. I would want to catch a SyntaxError in an eval (for example) so I see the logic now. Again, many thanks for your excellent answers!

Answer 2

No, that code will throw a SyntaxError:

If you don't know the exception your code might throw, you can capture for just Exception. Doing so will get all built-in, non-system-exiting exceptions:

except ValueError:
 print "the input is Invaild(dd.mm.year)"
except Exception as e:
 print "Unknown error"
 print e

Answer 3

You can access the Error Type in python3 using type().__name__

e.g.

try:
 ...
except Exception as err:
 print(f'Error: {str(err)}, Type: {type(err).__name__}')
 ...
...