Scrapy <TD>解析对齐的麻烦

Question

我尝试只解析html表中item和Skill Cap列的数据：http://ffxi.allakhazam.com/dyn/guilds/Alchemy.html

在解析时，我遇到了对齐问题，因为我的脚本是从其他列解析的。

import scrapy

class parser(scrapy.Spider):
    name = "recipe_table"
    start_urls = ['http://ffxi.allakhazam.com/dyn/guilds/Alchemy.html'] 

    def parse(self, response):
        for row in response.xpath('//*[@class="datatable sortable"]//tr'):
            data = row.xpath('td//text()').extract()
            if not data:  # skip empty row
                continue
            yield {
                'name': data[0],
                'cap': data[1],
             #   'misc': data[2]

            }

结果:当scrapy runspider cap.py -t json到达第3行时，来自非预期列的数据将被解析。我不确定选择是怎么回事。

2019-05-09 19:41:28 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://ffxi.allakhazam.com/dyn/guilds/Alchemy.html> (referer: None)
2019-05-09 19:41:28 [scrapy.core.scraper] DEBUG: Scraped from <200 http://ffxi.allakhazam.com/dyn/guilds/Alchemy.html>
{'item_name': u'Banquet Set', 'cap': u'0'}
2019-05-09 19:41:28 [scrapy.core.scraper] DEBUG: Scraped from <200 http://ffxi.allakhazam.com/dyn/guilds/Alchemy.html>
{'item_name': u'Banquet Table', 'cap': u'0'}
2019-05-09 19:41:28 [scrapy.core.scraper] DEBUG: Scraped from <200 http://ffxi.allakhazam.com/dyn/guilds/Alchemy.html>
{'item_name': u'Cermet Kilij', 'cap': u'Cermet Kilij +1'}

Answer 1

使用XPath显式设置源列如何：

for row in response.xpath('//*[@class="datatable sortable"]//tr'):
    yield {
        'name': row.xpath('./td[1]/text()').extract_first(),
        'cap': row.xpath('./td[3]/text()').extract_first(),
     #   'misc': etc.
    }