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<table width="100%" summary="page for xml_find_all {xml2}"><tr><td>xml_find_all {xml2}</td><td style="text-align: right;">R Documentation</td></tr></table>

<h2>Find nodes that match an xpath expression.</h2>

<h3>Description</h3>

<p>Xpath is like regular expressions for trees - it's worth learning if
you're trying to extract nodes from arbitrary locations in a document.
Use <code>xml_find_all</code> to find all matches - if there's no match you'll
get an empty result. Use <code>xml_find_first</code> to find a specific match -
if there's no match you'll get an <code>xml_missing</code> node.
</p>

<h3>Usage</h3>

<pre>
xml_find_all(x, xpath, ns = xml_ns(x))

xml_find_first(x, xpath, ns = xml_ns(x))

xml_find_num(x, xpath, ns = xml_ns(x))

xml_find_chr(x, xpath, ns = xml_ns(x))

xml_find_lgl(x, xpath, ns = xml_ns(x))
</pre>

<h3>Arguments</h3>

<table summary="R argblock">
<tr valign="top"><td><code>x</code></td>
<td>
<p>A document, node, or node set.</p>
</td></tr>
<tr valign="top"><td><code>xpath</code></td>
<td>
<p>A string containing a xpath (1.0) expression.</p>
</td></tr>
<tr valign="top"><td><code>ns</code></td>
<td>
<p>Optionally, a named vector giving prefix-url pairs, as produced
by <code><a href="xml_ns.html">xml_ns()</a></code>. If provided, all names will be explicitly
qualified with the ns prefix, i.e. if the element <code>bar</code> is defined
in namespace <code>foo</code>, it will be called <code>foo:bar</code>. (And
similarly for attributes). Default namespaces must be given an explicit
name. The ns is ignored when using <code><a href="xml_name.html">xml_name&lt;-()</a></code> and
<code><a href="xml_name.html">xml_set_name()</a></code>.</p>
</td></tr>
</table>

<h3>Value</h3>

<p><code>xml_find_all</code> always returns a nodeset: if there are no matches
the nodeset will be empty. The result will always be unique; repeated
nodes are automatically de-duplicated.
</p>
<p><code>xml_find_first</code> returns a node if applied to a node, and a nodeset
if applied to a nodeset. The output is <em>always</em> the same size as
the input. If there are no matches, <code>xml_find_first</code> will return a
missing node; if there are multiple matches, it will return the first
only.
</p>
<p><code>xml_find_num</code>, <code>xml_find_chr</code>, <code>xml_find_lgl</code> return
numeric, character and logical results respectively.
</p>

<h3>Deprecated functions</h3>

<p><code>xml_find_one()</code> has been deprecated. Instead use
<code>xml_find_first()</code>.
</p>

<p><code><a href="xml_ns_strip.html">xml_ns_strip()</a></code> to remove the default namespaces
</p>

<h3>Examples</h3>

<pre>
x &lt;- read_xml("&lt;foo&gt;&lt;bar&gt;&lt;baz/&gt;&lt;/bar&gt;&lt;baz/&gt;&lt;/foo&gt;")
xml_find_all(x, ".//baz")
xml_path(xml_find_all(x, ".//baz"))

# Note the difference between .// and //
# //  finds anywhere in the document (ignoring the current node)
# .// finds anywhere beneath the current node
(bar &lt;- xml_find_all(x, ".//bar"))
xml_find_all(bar, ".//baz")
xml_find_all(bar, "//baz")

# Find all vs find one -----------------------------------------------------
x &lt;- read_xml("&lt;body&gt;
  &lt;p&gt;Some &lt;b&gt;text&lt;/b&gt;.&lt;/p&gt;
  &lt;p&gt;Some &lt;b&gt;other&lt;/b&gt; &lt;b&gt;text&lt;/b&gt;.&lt;/p&gt;
  &lt;p&gt;No bold here!&lt;/p&gt;
&lt;/body&gt;")
para &lt;- xml_find_all(x, ".//p")

# If you apply xml_find_all to a nodeset, it finds all matches,
# de-duplicates them, and returns as a single list. This means you
# never know how many results you'll get
xml_find_all(para, ".//b")

# xml_find_first only returns the first match per input node. If there are 0
# matches it will return a missing node
xml_find_first(para, ".//b")
xml_text(xml_find_first(para, ".//b"))

# Namespaces ---------------------------------------------------------------
# If the document uses namespaces, you'll need use xml_ns to form
# a unique mapping between full namespace url and a short prefix
x &lt;- read_xml('
 &lt;root xmlns:f = "http://foo.com" xmlns:g = "http://bar.com"&gt;
   &lt;f:doc&gt;&lt;g:baz /&gt;&lt;/f:doc&gt;
   &lt;f:doc&gt;&lt;g:baz /&gt;&lt;/f:doc&gt;
 &lt;/root&gt;
')
xml_find_all(x, ".//f:doc")
xml_find_all(x, ".//f:doc", xml_ns(x))
</pre>

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