使用scrapy中的itemloader返回给定xpath找不到的项目的默认响应

Question

I need to return default value when no value is returned by the specified xpath in itemloader. Here is a bit of my spider. Am using very basic version of the itemloader :

il = ItemLoader(item = HomesItem(), response=response)
il.add_xpath('Company_Name', u'//*[@id="anchor_realtorOutline"]/div[1]/table/tbody/tr/th[contains(text(), "会社名")]/following-sibling::td/p[1]/ruby/text()')

So if this xpath does not return a value then i want to store N/A in place of it. Somewhat like we do here: .extract_first(default="N/A") and i need to use itemloader to concatenate a few xpaths for the same field. Sorry if this is silly , am not very good at scrapy yet. Thanks.

Answer 1

You can try to add xpath, then check is the field set or not, and then add default value in case field is empty. Like here:

il = ItemLoader(item = HomesItem(), response=response)
il.add_xpath('Company_Name', u'...')
if not il.get_output_value('Company_Name'):
    il.add_value('Company_Name', 'N/A')