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<div class="section" id="link-classes">
<h1>Link classes<a class="headerlink" href="#link-classes" title="Permalink to this headline">¶</a></h1>
<div class="section" id="the-link-class">
<span id="linkclassdescr"></span><h2>The Link class<a class="headerlink" href="#the-link-class" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt id="tables.link.Link">
<em class="property">class </em><tt class="descclassname">tables.link.</tt><tt class="descname">Link</tt><big>(</big><em>parentnode</em>, <em>name</em>, <em>target=None</em>, <em>_log=False</em><big>)</big><a class="reference internal" href="../../_modules/tables/link.html#Link"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#tables.link.Link" title="Permalink to this definition">¶</a></dt>
<dd><p>Abstract base class for all PyTables links.</p>
<p>A link is a node that refers to another node. The Link class inherits from
Node class and the links that inherits from Link are SoftLink and
ExternalLink. There is not a HardLink subclass because hard links behave
like a regular Group or Leaf. Contrarily to other nodes, links cannot have
HDF5 attributes. This is an HDF5 library limitation that might be solved
in future releases.</p>
<p>See <a class="reference internal" href="../tutorials.html#linkstutorial"><em>Using links for more convenient access to nodes</em></a> for a small tutorial on how to work with links.</p>
<p class="rubric">Link attributes</p>
<dl class="attribute">
<dt id="tables.Link.target">
<tt class="descname">target</tt><a class="headerlink" href="#tables.Link.target" title="Permalink to this definition">¶</a></dt>
<dd><p>The path string to the pointed node.</p>
</dd></dl>
</dd></dl>
<div class="section" id="link-instance-variables">
<h3>Link instance variables<a class="headerlink" href="#link-instance-variables" title="Permalink to this headline">¶</a></h3>
<dl class="attribute">
<dt id="tables.link.Link._v_attrs">
<tt class="descclassname">Link.</tt><tt class="descname">_v_attrs</tt><a class="reference internal" href="../../_modules/tables/link.html#Link._v_attrs"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#tables.link.Link._v_attrs" title="Permalink to this definition">¶</a></dt>
<dd><p>A <em>NoAttrs</em> instance replacing the typical <em>AttributeSet</em> instance of
other node objects. The purpose of <em>NoAttrs</em> is to make clear that
HDF5 attributes are not supported in link nodes.</p>
</dd></dl>
</div>
<div class="section" id="link-methods">
<h3>Link methods<a class="headerlink" href="#link-methods" title="Permalink to this headline">¶</a></h3>
<p>The following methods are useful for copying, moving, renaming and removing
links.</p>
<dl class="method">
<dt id="tables.link.Link.copy">
<tt class="descclassname">Link.</tt><tt class="descname">copy</tt><big>(</big><em>newparent=None</em>, <em>newname=None</em>, <em>overwrite=False</em>, <em>createparents=False</em><big>)</big><a class="reference internal" href="../../_modules/tables/link.html#Link.copy"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#tables.link.Link.copy" title="Permalink to this definition">¶</a></dt>
<dd><p>Copy this link and return the new one.</p>
<p>See <a class="reference internal" href="hierarchy_classes.html#tables.Node._f_copy" title="tables.Node._f_copy"><tt class="xref py py-meth docutils literal"><span class="pre">Node._f_copy()</span></tt></a> for a complete explanation of the arguments.
Please note that there is no recursive flag since links do not have
child nodes.</p>
</dd></dl>
<dl class="method">
<dt id="tables.link.Link.move">
<tt class="descclassname">Link.</tt><tt class="descname">move</tt><big>(</big><em>newparent=None</em>, <em>newname=None</em>, <em>overwrite=False</em><big>)</big><a class="reference internal" href="../../_modules/tables/link.html#Link.move"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#tables.link.Link.move" title="Permalink to this definition">¶</a></dt>
<dd><p>Move or rename this link.</p>
<p>See <a class="reference internal" href="hierarchy_classes.html#tables.Node._f_move" title="tables.Node._f_move"><tt class="xref py py-meth docutils literal"><span class="pre">Node._f_move()</span></tt></a> for a complete explanation of the arguments.</p>
</dd></dl>
<dl class="method">
<dt id="tables.link.Link.remove">
<tt class="descclassname">Link.</tt><tt class="descname">remove</tt><big>(</big><big>)</big><a class="reference internal" href="../../_modules/tables/link.html#Link.remove"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#tables.link.Link.remove" title="Permalink to this definition">¶</a></dt>
<dd><p>Remove this link from the hierarchy.</p>
</dd></dl>
<dl class="method">
<dt id="tables.link.Link.rename">
<tt class="descclassname">Link.</tt><tt class="descname">rename</tt><big>(</big><em>newname=None</em>, <em>overwrite=False</em><big>)</big><a class="reference internal" href="../../_modules/tables/link.html#Link.rename"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#tables.link.Link.rename" title="Permalink to this definition">¶</a></dt>
<dd><p>Rename this link in place.</p>
<p>See <a class="reference internal" href="hierarchy_classes.html#tables.Node._f_rename" title="tables.Node._f_rename"><tt class="xref py py-meth docutils literal"><span class="pre">Node._f_rename()</span></tt></a> for a complete explanation of the arguments.</p>
</dd></dl>
</div>
</div>
<div class="section" id="the-softlink-class">
<span id="softlinkclassdescr"></span><h2>The SoftLink class<a class="headerlink" href="#the-softlink-class" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt id="tables.link.SoftLink">
<em class="property">class </em><tt class="descclassname">tables.link.</tt><tt class="descname">SoftLink</tt><big>(</big><em>parentnode</em>, <em>name</em>, <em>target=None</em>, <em>_log=False</em><big>)</big><a class="reference internal" href="../../_modules/tables/link.html#SoftLink"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#tables.link.SoftLink" title="Permalink to this definition">¶</a></dt>
<dd><p>Represents a soft link (aka symbolic link).</p>
<p>A soft link is a reference to another node in the <em>same</em> file hierarchy.
Getting access to the pointed node (this action is called <em>dereferrencing</em>)
is done via the __call__ special method (see below).</p>
</dd></dl>
<div class="section" id="softlink-special-methods">
<h3>SoftLink special methods<a class="headerlink" href="#softlink-special-methods" title="Permalink to this headline">¶</a></h3>
<p>The following methods are specific for dereferrencing and representing soft
links.</p>
<dl class="method">
<dt id="tables.link.SoftLink.__call__">
<tt class="descclassname">SoftLink.</tt><tt class="descname">__call__</tt><big>(</big><big>)</big><a class="reference internal" href="../../_modules/tables/link.html#SoftLink.__call__"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#tables.link.SoftLink.__call__" title="Permalink to this definition">¶</a></dt>
<dd><p>Dereference <cite>self.target</cite> and return the object.</p>
<p class="rubric">Examples</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="n">f</span><span class="o">=</span><span class="n">tables</span><span class="o">.</span><span class="n">open_file</span><span class="p">(</span><span class="s">'data/test.h5'</span><span class="p">)</span>
<span class="gp">>>> </span><span class="k">print</span> <span class="n">f</span><span class="o">.</span><span class="n">root</span><span class="o">.</span><span class="n">link0</span>
<span class="go">/link0 (SoftLink) -> /another/path</span>
<span class="gp">>>> </span><span class="k">print</span> <span class="n">f</span><span class="o">.</span><span class="n">root</span><span class="o">.</span><span class="n">link0</span><span class="p">()</span>
<span class="go">/another/path (Group) ''</span>
</pre></div>
</div>
</dd></dl>
<dl class="method">
<dt id="tables.link.SoftLink.__str__">
<tt class="descclassname">SoftLink.</tt><tt class="descname">__str__</tt><big>(</big><big>)</big><a class="reference internal" href="../../_modules/tables/link.html#SoftLink.__str__"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#tables.link.SoftLink.__str__" title="Permalink to this definition">¶</a></dt>
<dd><p>Return a short string representation of the link.</p>
<p class="rubric">Examples</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="n">f</span><span class="o">=</span><span class="n">tables</span><span class="o">.</span><span class="n">open_file</span><span class="p">(</span><span class="s">'data/test.h5'</span><span class="p">)</span>
<span class="gp">>>> </span><span class="k">print</span> <span class="n">f</span><span class="o">.</span><span class="n">root</span><span class="o">.</span><span class="n">link0</span>
<span class="go">/link0 (SoftLink) -> /path/to/node</span>
</pre></div>
</div>
</dd></dl>
</div>
</div>
<div class="section" id="the-externallink-class">
<h2>The ExternalLink class<a class="headerlink" href="#the-externallink-class" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt id="tables.link.ExternalLink">
<em class="property">class </em><tt class="descclassname">tables.link.</tt><tt class="descname">ExternalLink</tt><big>(</big><em>parentnode</em>, <em>name</em>, <em>target=None</em>, <em>_log=False</em><big>)</big><a class="reference internal" href="../../_modules/tables/link.html#ExternalLink"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#tables.link.ExternalLink" title="Permalink to this definition">¶</a></dt>
<dd><p>Represents an external link.</p>
<p>An external link is a reference to a node in <em>another</em> file.
Getting access to the pointed node (this action is called
<em>dereferencing</em>) is done via the <tt class="xref py py-meth docutils literal"><span class="pre">__call__()</span></tt> special method
(see below).</p>
<p class="rubric">ExternalLink attributes</p>
<dl class="attribute">
<dt id="tables.ExternalLink.extfile">
<tt class="descname">extfile</tt><a class="headerlink" href="#tables.ExternalLink.extfile" title="Permalink to this definition">¶</a></dt>
<dd><p>The external file handler, if the link has been dereferenced.
In case the link has not been dereferenced yet, its value is
None.</p>
</dd></dl>
</dd></dl>
<div class="section" id="externallink-methods">
<h3>ExternalLink methods<a class="headerlink" href="#externallink-methods" title="Permalink to this headline">¶</a></h3>
<dl class="method">
<dt id="tables.link.ExternalLink.umount">
<tt class="descclassname">ExternalLink.</tt><tt class="descname">umount</tt><big>(</big><big>)</big><a class="reference internal" href="../../_modules/tables/link.html#ExternalLink.umount"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#tables.link.ExternalLink.umount" title="Permalink to this definition">¶</a></dt>
<dd><p>Safely unmount self.extfile, if opened.</p>
</dd></dl>
</div>
<div class="section" id="externallink-special-methods">
<h3>ExternalLink special methods<a class="headerlink" href="#externallink-special-methods" title="Permalink to this headline">¶</a></h3>
<p>The following methods are specific for dereferrencing and representing
external links.</p>
<dl class="method">
<dt id="tables.link.ExternalLink.__call__">
<tt class="descclassname">ExternalLink.</tt><tt class="descname">__call__</tt><big>(</big><em>**kwargs</em><big>)</big><a class="reference internal" href="../../_modules/tables/link.html#ExternalLink.__call__"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#tables.link.ExternalLink.__call__" title="Permalink to this definition">¶</a></dt>
<dd><p>Dereference self.target and return the object.</p>
<p>You can pass all the arguments supported by the <a class="reference internal" href="top_level.html#tables.open_file" title="tables.open_file"><tt class="xref py py-func docutils literal"><span class="pre">open_file()</span></tt></a>
function (except filename, of course) so as to open the referenced
external file.</p>
<p class="rubric">Examples</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="n">f</span><span class="o">=</span><span class="n">tables</span><span class="o">.</span><span class="n">open_file</span><span class="p">(</span><span class="s">'data1/test1.h5'</span><span class="p">)</span>
<span class="gp">>>> </span><span class="k">print</span> <span class="n">f</span><span class="o">.</span><span class="n">root</span><span class="o">.</span><span class="n">link2</span>
<span class="go">/link2 (ExternalLink) -> data2/test2.h5:/path/to/node</span>
<span class="gp">>>> </span><span class="n">plink2</span> <span class="o">=</span> <span class="n">f</span><span class="o">.</span><span class="n">root</span><span class="o">.</span><span class="n">link2</span><span class="p">(</span><span class="s">'a'</span><span class="p">)</span> <span class="c"># open in 'a'ppend mode</span>
<span class="gp">>>> </span><span class="k">print</span> <span class="n">plink2</span>
<span class="go">/path/to/node (Group) ''</span>
<span class="gp">>>> </span><span class="k">print</span> <span class="n">plink2</span><span class="o">.</span><span class="n">_v_filename</span>
<span class="go">'data2/test2.h5' # belongs to referenced file</span>
</pre></div>
</div>
</dd></dl>
<dl class="method">
<dt id="tables.link.ExternalLink.__str__">
<tt class="descclassname">ExternalLink.</tt><tt class="descname">__str__</tt><big>(</big><big>)</big><a class="reference internal" href="../../_modules/tables/link.html#ExternalLink.__str__"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#tables.link.ExternalLink.__str__" title="Permalink to this definition">¶</a></dt>
<dd><p>Return a short string representation of the link.</p>
<p class="rubric">Examples</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="n">f</span><span class="o">=</span><span class="n">tables</span><span class="o">.</span><span class="n">open_file</span><span class="p">(</span><span class="s">'data1/test1.h5'</span><span class="p">)</span>
<span class="gp">>>> </span><span class="k">print</span> <span class="n">f</span><span class="o">.</span><span class="n">root</span><span class="o">.</span><span class="n">link2</span>
<span class="go">/link2 (ExternalLink) -> data2/test2.h5:/path/to/node</span>
</pre></div>
</div>
</dd></dl>
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<h3><a href="../../index.html">Table Of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#">Link classes</a><ul>
<li><a class="reference internal" href="#the-link-class">The Link class</a><ul>
<li><a class="reference internal" href="#link-instance-variables">Link instance variables</a></li>
<li><a class="reference internal" href="#link-methods">Link methods</a></li>
</ul>
</li>
<li><a class="reference internal" href="#the-softlink-class">The SoftLink class</a><ul>
<li><a class="reference internal" href="#softlink-special-methods">SoftLink special methods</a></li>
</ul>
</li>
<li><a class="reference internal" href="#the-externallink-class">The ExternalLink class</a><ul>
<li><a class="reference internal" href="#externallink-methods">ExternalLink methods</a></li>
<li><a class="reference internal" href="#externallink-special-methods">ExternalLink special methods</a></li>
</ul>
</li>
</ul>
</li>
</ul>
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