如何准确地从ODP中提取信息？[关闭]

要使用ODP数据，请下载RDF数据转储。RDF是XML格式；您将索引转储以将URL映射到描述；我将为此使用SQL数据库。

请注意，URL可以存在于转储中的多个位置。例如，堆栈溢出被两次列出。Google使用此条目中的文本作为网站描述，而Bing则使用此文本。

数据转储当然很大。在向数据库添加条目时，使用诸如ElementTree

iterparse()

<ExternalPage>

<d:Title>

<d:Description>

使用

lxml

from lxml import etree as ETimport gzipimport sqlite3conn = sqlite3.connect('/path/to/database')# create tablewith conn:    cursor = conn.cursor()    cursor.execute('''        CREATE TABLE IF NOT EXISTS odp_urls         (url text primary key, title text, description text)''')count = 0nsmap = {'d': 'http://purl.org/dc/elements/1.0/'}with gzip.open('content.rdf.u8.gz', 'rb') as content, conn:    cursor = conn.cursor()    for event, element in ET.iterparse(content, tag='{http://dmoz.org/rdf/}ExternalPage'):        url = element.attrib['about']        title = element.xpath('d:Title/text()', namespaces=nsmap)        description = element.xpath('d:Description/text()', namespaces=nsmap)        title, description = title and title[0] or '', description and description[0] or ''        # no longer need this, remove from memory again, as well as any preceding siblings        elem.clear()        while elem.getprevious() is not None: del elem.getparent()[0]        cursor.execute('INSERT OR REPLACE INTO odp_urls VALUES (?, ?, ?)', (url, title, description))        count += 1        if count % 1000 == 0: print 'Processed {} items'.format(count)