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https://www.iana.org/domains/arpa

我可以使用 xpath '//table[@id="arpa-table"]/tbody/tr/join((td[1], normalize-space(td[2])), x:cps( 9))' 与 xidel。但我想把东西RFC 3172放在第三列和第四/go/rfc3172列。有人让我知道你是怎么做的吗？

arpa▸   Reserved exclusively to support operationally-critical infrastructural identifier spaces as advised by the Internet Architecture Board RFC 3172¬
as112.arpa▸ For sinking DNS traffic for reverse IP address lookups and other applications RFC 7535¬
e164.arpa▸  For mapping E.164 numbers to Internet URIs RFC 6116¬
home.arpa▸  For non-unique use in residential home networks RFC 8375¬
in-addr-servers.arpa▸   For hosting authoritative name servers for the in-addr.arpa domain RFC 5855¬
in-addr.arpa▸   For mapping IPv4 addresses to Internet domain names RFC 1035¬
ip6-servers.arpa▸   For hosting authoritative name servers for the ip6.arpa domain RFC 5855¬
ip6.arpa▸   For mapping IPv6 addresses to Internet domain names RFC 3152¬
ipv4only.arpa▸  For detecting the presence of DNS64 and for learning the IPv6 prefix used for protocol translation RFC 7050¬
iris.arpa▸  For locating Internet Registry Information Services RFC 4698¬
uri.arpa▸   For resolving Uniform Resource Identifiers according to the Dynamic Delegation Discovery System RFC 3405 RFC 8958¬
urn.arpa▸   For resolving Uniform Resource Names according to the Dynamic Delegation Discovery System RFC 3405¬

第一行应该类似于

arpa▸   Reserved exclusively to support operationally-critical infrastructural identifier spaces as advised by the Internet Architecture Board▸ RFC 3172¬
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1 回答 1

1

默认情况下xidel打印节点/元素的字符串值 ( string())。正如 E. Lenz 所说，它是“其所有后代文本节点的字符串值的串联”：

$ xidel -s https://www.iana.org/domains/arpa -e '
  //table[@id="arpa-table"]/tbody/tr[1]/td[2] ! (position(),.)
'
#or
$ xidel -s https://www.iana.org/domains/arpa -e '
  //table[@id="arpa-table"]/tbody/tr[1]/td[2]/string() ! (position(),.)
'
1
Reserved exclusively to support operationally-critical infrastructural identifier spaces as advised by the Internet Architecture Board

                RFC 3172

如您所见，1 个项目/节点。
这就是为什么normalize-space(td[2])返回Reserved exclusively [...] RFC 3172。

text()另一方面，您将获得节点/元素的直接文本节点：

$ xidel -s https://www.iana.org/domains/arpa -e '
  //table[@id="arpa-table"]/tbody/tr[1]/td[2]/text() ! (position(),.)
'
1
Reserved exclusively to support operationally-critical infrastructural identifier spaces as advised by the Internet Architecture Board
2



3

或者它的所有后代文本节点：

$ xidel -s https://www.iana.org/domains/arpa -e '
  //table[@id="arpa-table"]/tbody/tr[1]/td[2]//text() ! (position(),.)
'
1
Reserved exclusively to support operationally-critical infrastructural identifier spaces as advised by the Internet Architecture Board
2



3
RFC 3172
4

如您所见，有 3 个和 4 个不同的项目/节点。

要获得第一个文本节点，只需td[2]/text()[1]这样做，但normalize-space(td[2]/text())甚至normalize-space(td[2]//text())也可以。

于 2021-02-05T17:45:14.347 回答