python学习笔记：xpath+css

xpath用法

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#提取文章的具体字段
title = response.xpath('//div[@class="entry-header"]/h1/text()').extract_first("")
create_date = response.xpath("//p[@class='entry-meta-hide-on-mobile']/text()").extract()[0].strip().replace("·","").strip()
praise_nums = response.xpath("//span[contains(@class, 'vote-post-up')]/h10/text()").extract()[0]
fav_nums = response.xpath("//span[contains(@class, 'bookmark-btn')]/text()").extract()[0]
match_re = re.match(".*?(\d+).*", fav_nums)
if match_re:
     fav_nums = match_re.group(1)

comment_nums = response.xpath("//a[@href='#article-comment']/span/text()").extract()[0]
match_re = re.match(".*?(\d+).*", comment_nums)
if match_re:
    comment_nums = match_re.group(1)

content = response.xpath("//div[@class='entry']").extract()[0]

tag_list = response.xpath("//p[@class='entry-meta-hide-on-mobile']/a/text()").extract()
tag_list = [element for element in tag_list if not element.strip().endswith("评论")]
tags = ",".join(tag_list)

CSS用法

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front_image_url = response.meta.get("front_image_url", "")  #文章封面图
title = response.css(".entry-header h1::text").extract()[0]
create_date = response.css("p.entry-meta-hide-on-mobile::text").extract()[0].strip().replace("·","").strip()
praise_nums = response.css(".vote-post-up h10::text").extract()[0]
fav_nums = response.css(".bookmark-btn::text").extract()[0]
match_re = re.match(".*?(\d+).*", fav_nums)
if match_re:
    fav_nums = int(match_re.group(1))
else:
    fav_nums = 0

comment_nums = response.css("a[href='#article-comment'] span::text").extract()[0]
match_re = re.match(".*?(\d+).*", comment_nums)
if match_re:
    comment_nums = int(match_re.group(1))
else:
    comment_nums = 0

content = response.css("div.entry").extract()[0]

tag_list = response.css("p.entry-meta-hide-on-mobile a::text").extract()
tag_list = [element for element in tag_list if not element.strip().endswith("评论")]
tags = ",".join(tag_list)

#组装数据
article_item["url_object_id"] = get_md5(response.url)
article_item["title"] = title
article_item["url"] = response.url
try:
    create_date = datetime.datetime.strptime(create_date, "%Y/%m/%d").date()
except Exception as e:
    create_date = datetime.datetime.now().date()
article_item["create_date"] = create_date
article_item["front_image_url"] = [front_image_url]
article_item["praise_nums"] = praise_nums
article_item["comment_nums"] = comment_nums
article_item["fav_nums"] = fav_nums
article_item["tags"] = tags
article_item["content"] = content