我可以在 python 中为 dict 动态创建密钥吗？

Question

I am creating a spider in Scrapy. And I want to scrape table in this way:

• Take every <tr>
• Use <th> as key and <td> as content

The code I came up with is this.

def parse(self, response):
        item = {}
        item['code'] = response.xpath('//meta[@itemprop="sku"]/@content').extract_first()
        tables = response.css('.technical-specs')
        for table in tables:
            specs = tables.xpath('tbody/tr')
            for s in specs:
                key = s.xpath('th/text()').extract_first().replace(" ", "_").replace("(", "_").replace(")", "_").replace("/", "").lower()
                value = s.xpath('td/text()').extract_first()
                item[key] = value


        return item

But it is not working. Is this posible to achieve?

Answer 1

You need to create a dict instance and then add the items inside the loop. Eg:

my_dict = dict() # Can be {} to

for item in items:
  key = item.key
  value = item.value
  my_dict[key] = value

Regards

Answer 2

The, now working, code of parse function is updated in my question details. Problem was not in the way loop or dictionary was implemented, but in how I extracted data. I was using .extract() which makes response unicode and "unscrapable". Removing.extract was the fix.