我是一个Python新手，正在尝试使用scrapy进行项目。 Scrapy 0.19安装在我的centos(linux 2.6.32)上，我按照scrapy文档页面上的说明进行操作，但发现scrapy shell找不到'sel'对象，这是我的步骤:
[root@localhost rpm]# scrapy shell http://doc.scrapy.org/en/latest/_static/selectors-sample1.html
2014-03-02 06:33:23+0800 [scrapy] INFO: Scrapy 0.19.0 started (bot: scrapybot)
2014-03-02 06:33:23+0800 [scrapy] DEBUG: Optional features available: ssl, http11, libxml2
2014-03-02 06:33:23+0800 [scrapy] DEBUG: Overridden settings: {'LOGSTATS_INTERVAL': 0}
2014-03-02 06:33:23+0800 [scrapy] DEBUG: Enabled extensions: TelnetConsole, CloseSpider, WebService, CoreStats, SpiderState
2014-03-02 06:33:23+0800 [scrapy] DEBUG: Enabled downloader middlewares: HttpAuthMiddleware, DownloadTimeoutMiddleware, UserAgentMiddleware, RetryMiddleware, DefaultHeadersMiddleware, MetaRefreshMiddleware, HttpCompressionMiddleware, RedirectMiddleware, CookiesMiddleware, ChunkedTransferMiddleware, DownloaderStats
2014-03-02 06:33:23+0800 [scrapy] DEBUG: Enabled spider middlewares: HttpErrorMiddleware, OffsiteMiddleware, RefererMiddleware, UrlLengthMiddleware, DepthMiddleware
2014-03-02 06:33:23+0800 [scrapy] DEBUG: Enabled item pipelines:
2014-03-02 06:33:23+0800 [scrapy] DEBUG: Telnet console listening on 0.0.0.0:6023
2014-03-02 06:33:23+0800 [scrapy] DEBUG: Web service listening on 0.0.0.0:6080
2014-03-02 06:33:23+0800 [default] INFO: Spider opened
2014-03-02 06:33:24+0800 [default] DEBUG: Crawled (200) <GET
http://doc.scrapy.org/en/latest/_static/selectors-sample1.html> (referer: None)
[s] Available Scrapy objects:
[s] hxs <HtmlXPathSelector xpath=None data=u'<html><head><base href="http://example.c'>
[s] item {}
[s] request <GET http://doc.scrapy.org/en/latest/_static/selectors-sample1.html>
[s] response <200 http://doc.scrapy.org/en/latest/_static/selectors-sample1.html>
[s] settings <CrawlerSettings module=None>
[s] spider <BaseSpider 'default' at 0x3668ed0>
[s] Useful shortcuts:
[s] shelp() Shell help (print this help)
[s] fetch(req_or_url) Fetch request (or URL) and update local objects
[s] view(response) View response in a browser
>>> sel.xpath('//title/text()')
Traceback (most recent call last):
File "<console>", line 1, in <module>
NameError: name 'sel' is not defined
>>>
谁能告诉我怎么解决？提前谢谢
最佳答案
sel 对象是在 0.20 版本中添加的。当您运行 shell 命令时，它会告诉您可以使用哪些对象，在您的例子中，hxs 具有类似的行为:
>>> hxs.select('//title/text()')
您应该首先尝试阅读文档。在选择器部分中，非常清楚地解释了如何根据当前版本使用它们。
关于scrapy shell无法识别 'sel'对象，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/22115982/