Item default value is appended to the processor_in output in ItemLoader about itemloaders HOT 2 OPEN

Hello @wRAR , this is related to how itemloaders build the items.

What's happening here is that ItemLoader will create an instance of ArticleItem without values. Because of that, the user_rating is set to -999 during the instance creation, and ItemLoader will assume as the first value discovered to that field. This is the same behaviour as to passing an already pre-filled dictionary to an item loader:

>>> loader = RappiLoader(item={"user_rating": 2.5})
>>> loader.add_value("user_rating", 0)  # Add fallback value in case user_rating was not defined 
>>> loader.load_item()
{'user_rating': 2.5}

In this case however, the expectation would be to keep the initial value already provided.

I think this shouldn't be fixed. The list of values are always added in the same order. Then, is up to the user to decide what to do with them - e.g. select the first one, last one, all of them, apply some filters, or manipulate them-.

You can implementing a custom selector that fits your needs.

from itemloaders.

Moving this to itemloaders, though on a second thought (and without checking any code) it may be, though not likely, itemdapter-specific.

from itemloaders.