selectr: Translate CSS Selectors to XPath Expressions

> library(selectr)

バージョン: 0.3.0

関数名 概略
css_to_xpath Translate a CSS selector to an equivalent XPath expression.
querySelectorAll Find nodes that match a group of CSS selectors in an XML tree.

css_to_xpath

Arguments

  • selector
  • prefix
  • translator
> css_to_xpath(".testclass")

[1] "descendant-or-self::*[@class and contains(concat(' ', normalize-space(@class), ' '), ' testclass ')]"

> css_to_xpath("#testid", prefix = "")

[1] "*[@id = 'testid']"

> css_to_xpath("#testid .testclass")

[1] "descendant-or-self::*[@id = 'testid']/descendant::*[@class and contains(concat(' ', normalize-space(@class), ' '), ' testclass ')]"

querySelectorAll

Arguments

  • doc
  • selector
  • ns
  • prefix
  • ...
> svgdoc <- xml2::read_xml(system.file("demos/svg-mathml.svg",
+                                  package = "selectr"))
> 
> querySelectorNS(svgdoc, "svg|script",
+                   c(svg = "http://www.w3.org/2000/svg"))

{xml_node}
<script type="application/ecmascript" href="test2.svg.coords.js">

> querySelectorAllNS(svgdoc, "svg|script",
+                      c(svg = "http://www.w3.org/2000/svg"))

{xml_nodeset (2)}
[1] <script type="application/ecmascript" xlink:href="test2.svg.coords.j ...
[2] <script type="application/ecmascript" xlink:href="test2.svg.convert. ...

> exdoc <- xml2::read_xml('<a><b class="aclass"/><c id="anid"/></a>')
> querySelector(exdoc, "#anid")

{xml_node}
<c id="anid">

> querySelector(exdoc, ".aclass")

{xml_node}
<b class="aclass">

> querySelector(exdoc, "b, c")

{xml_node}
<b class="aclass">

> querySelectorAll(exdoc, "b, c")

{xml_nodeset (2)}
[1] <b class="aclass"/>
[2] <c id="anid"/>

> querySelectorAll(exdoc, "b")

{xml_nodeset (1)}
[1] <b class="aclass"/>

> querySelector(exdoc, "d")

NULL

> querySelectorAll(exdoc, "d")

{xml_nodeset (0)}

> library(rvest)
> x <- read_html("https://github.com/sjp/selectr")
> querySelector(x, ".anchor")

{xml_node}
<a id="user-content-selectr" class="anchor" href="#selectr" aria-hidden="true">
[1] <svg aria-hidden="true" class="octicon octicon-link" height="16" ver ...