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Python 中的一个逻辑写法

  •   
  •   Ewig · Dec 3, 2018 · 2295 views
    This topic created in 2897 days ago, the information mentioned may be changed or developed.
    if response.xpath('//link[contains(@rel,"apple-touch-icon-precomposed")]/@href') :
    apple_touch_url = response.xpath('//link[contains(@rel,"apple-touch-icon-precomposed")]/@href').extract()
    apple_touch_url=[link for link in apple_touch_url if 'https' in link or 'http' in link ]
    item['logo'] = apple_touch_url
    if not apple_touch_url:
    ‘这里没有这个列表我想走 elif 的逻辑’但是好像没有这样的语法，求人指教，谢谢

    elif response.xpath('//link[contains(@rel,"icon")]/@href'):
    rel_url=response.xpath('//link[contains(@rel,"icon")]/@href').extract()
    item['logo']=rel_url
    print(rel_url)
    Supplement 1  ·  Dec 3, 2018
    if response.xpath('//link[contains(@rel,"apple-touch-icon-precomposed")]/@href') :
    apple_touch_url = response.xpath('//link[contains(@rel,"apple-touch-icon-precomposed")]/@href').extract()
    apple_touch_url=[link for link in apple_touch_url if 'https' in link or 'http' in link ]
    item['logo'] = apple_touch_url
    if not apple_touch_url:
    ‘这里没有这个列表我想走 elif 的逻辑’但是好像没有这样的语法，求人指教，谢谢

    elif response.xpath('//link[contains(@rel,"icon")]/@href'):
    rel_url=response.xpath('//link[contains(@rel,"icon")]/@href').extract()
    item['logo']=rel_url
    print(rel_url)
    Supplement 2  ·  Dec 3, 2018
    if response.xpath('//link[contains(@rel,"apple-touch-icon-precomposed")]/@href') :
    apple_touch_url = response.xpath('//link[contains(@rel,"apple-touch-icon-precomposed")]/@href').extract()
    apple_touch_url=[link for link in apple_touch_url if 'https' in link or 'http' in link ]
    item['logo'] = apple_touch_url
    if not apple_touch_url:
    ‘这里没有这个列表我想走 elif 的逻辑’但是好像没有这样的语法，求人指教，谢谢

    elif response.xpath('//link[contains(@rel,"icon")]/@href'):
    rel_url=response.xpath('//link[contains(@rel,"icon")]/@href').extract()
    item['logo']=rel_url
    print(rel_url)
  • LINK
  • xpath
  • contains
  • response
    8 replies  •  2018-12-03 16:48:30 +08:00
    kimchan
    kimchan
    Dec 3, 2018
    1
    这... 没法看啊..
    whoami9894
    whoami9894
    Dec 3, 2018 via Android
    2
    楼下有人能理解楼主想表达啥吗
    holajamc
    holajamc
    Dec 3, 2018
    3
    if not apple_touch_url and response.xpath('//link[contains(@rel,"icon")]/@href'):
    猜的）
    kimchan
    kimchan
    Dec 3, 2018
    4
    我猜是他需要在最上边加一句: apple_touch_url = None
    ant2017
    ant2017
    Dec 3, 2018
    5
    我猜是判断变量是否定义？
    'apple_touch_url' in dir()
    Ewig
    Ewig
    OP
    Dec 3, 2018
    6
    @kimchan 我不知道怎么排版
    Trim21
    Trim21
    Dec 3, 2018
    7
    用 markdown 语法
    hahastudio
    hahastudio
    Dec 3, 2018
    8
    @Ewig 贴 gist link 到评论里
    https://gist.github.com/
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