UnboundLocalError：在赋值之前引用了局部变量“区域”

Question

I am trying to create an object but stacked with this problem, but it seams for me that i didn't make any mistake.

def handle(self, *args, **options):
        for entry in get_dataset():
            oblast = Place.objects.get_or_create(name=entry.get('OBL_NAME'))
            if entry.get('REGION_NAME') is not None:
                region = Place.objects.get_or_create(name=entry.get('REGION_NAME'),
                                            parent=oblast)
            if entry.get('CITY_NAME') is not None:
                city = Place.objects.get_or_create(name=entry.get('CITY_NAME'),
                                            parent=region)

I could not understand why region variable doesn't work

Answer 1

In you last part you have

city = Place.objects.get_or_create(..., parent=region)

The variable region does not seem to be defined if the first if is false (the code execution never gets to assign a value to region in that case).

Maybe you need to initialize the variable outside of the first if (maybe like region = None or something just before the first if ). Here is a example of how you could do it, but the exact way depends on the rest of your code:

oblast = Place.objects.get_or_create(name=entry.get('OBL_NAME'))

region = None
if entry.get('REGION_NAME') is not None:
    region = ...

if entry.get('CITY_NAME') is not None:
    city = Place.objects.get_or_create(
        name=entry.get('CITY_NAME'),
        parent=region)

Answer 2

Somehow your code doesn't meet your first if condition and therefore your region variable doesn't get created. You could do something like this:

def handle(self, *args, **options):
    for entry in get_dataset():
        oblast = Place.objects.get_or_create(name=entry.get('OBL_NAME'))
        if entry.get('REGION_NAME') is not None:
            region = Place.objects.get_or_create(name=entry.get('REGION_NAME'),
                                        parent=oblast)
        if entry.get('CITY_NAME') is not None and region:
            city = Place.objects.get_or_create(name=entry.get('CITY_NAME'),
                                        parent=region)
        else:
            city = Place.objecys.get_or_create(name=entry.get('CITY_NAME'))