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Code Releases Wiki Activity

Don’t use follow_all where a single item is expected (#4)

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Adrián Chaves 2019-12-02 16:47:44 +01:00 committed by elacuesta
parent dd12f5fdcd
commit 5980b0f284
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11
docs/intro/tutorial.rst
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@ -616,20 +616,19 @@ instance; you still have to yield this Request.
You can also pass a selector to ``response.follow`` instead of a string;
this selector should extract necessary attributes::
for href in response.css('li.next a::attr(href)'):
yield response.follow(href, callback=self.parse)
href = response.css('li.next a::attr(href)')[0]
yield response.follow(href, callback=self.parse)
For ``<a>`` elements there is a shortcut: ``response.follow`` uses their href
attribute automatically. So the code can be shortened further::
for a in response.css('li.next a'):
yield response.follow(a, callback=self.parse)
a = response.css('li.next a')[0]
yield response.follow(a, callback=self.parse)
To create multiple requests from an iterable, you can use
:meth:`response.follow_all <scrapy.http.TextResponse.follow_all>` instead::
links = response.css('li.next a')
yield from response.follow_all(links, callback=self.parse)
yield from response.follow_all(response.css('a'), callback=self.parse)
More examples and patterns