CODE:
def somef(*iterable_objs, positions):
try:
# some statement
except TypeError:
print('Argument \'positions\' is missing')
return False
>>>somef([1,2,3], 'abc', (4,5,6))
TypeError is raised because argument positions is missing.
I would like to know if there is a method how to handle this exception
You can't use *args with other positional arguments following; positions is regarded as a keyword-only argument instead. Because it has no default value, it is still required.
Either give positions a default value to remove the requirement that it is always specified when calling:
def somef(*iterable_objs, positions=None):
if positions is None:
# calculate a default instead
positions = range(len(iterable_objs))
or pass in a positions keyword argument explicitly:
somef([1,2,3], 'abc', positions=(4,5,6))
Side-note: never use print() to signal an error condition. The end user doesn't want to know that the programmer made a mistake, the program needs to hear about the error. Use raise SomeException() instead.
TypeError when positions isn't provided, you might as well just not provide a default value and let Python raise that error for you. It's not clear what the questioner intended to do when positions isn't present, beyond perhaps a general sense that they wanted to "get rid of the errors".
print() to flag that an argument wasn't provided is definitely not the way to go either.
iterable_objs and align items based on positions etc.. Whole code works as i want, but i want to handle all 'possible' situations that might happen when. Thanks for advice about that Error raising!As guys already mentioned if you use positions argument after *iterable_objs it is treated as keyword-only argument but if you change the order of arguments everything will work fine.
def somef(positions, *iterable_objs):
positions argument with explicit keyword
positions have to be last? It's your code, you can put arguments in any order for functions you create.If you won't always require a value to be passed for it, just supply a default:
def somef(*iterable_objs, positions=None):
iterable_objsto capture all but the last positional argument andpositionsto capture the last? Did you wantpositionsto be keyword-only, but have the try-except handle what happens whenpositionsisn't provided? Were you trying to do something else?iterable_objs) and last one ispositionsONLY if key word is includedpositionsisn't provided. Catching exceptions is a bad thing if there's nothing you can reasonably do about them, as seems to be the case here.