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<div class="section" id="cds">
<h1>Cds<a class="headerlink" href="#cds" title="Permalink to this headline">¶</a></h1>
<dl class="class">
<dt id="astropy.io.ascii.cds.Cds">
<em class="property">class </em><tt class="descclassname">astropy.io.ascii.cds.</tt><tt class="descname">Cds</tt><big>(</big><em>readme=None</em><big>)</big><a class="reference external" href="http://github.com/astropy/astropy/tree/v0.2.4/astropy/io/ascii/cds.py#L198" title="Push the Edit button on the next page"><span class="edit-on-github viewcode-link"> [edit on github]</span></a><a class="reference internal" href="../_modules/astropy/io/ascii/cds.html#Cds"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#astropy.io.ascii.cds.Cds" title="Permalink to this definition">¶</a></dt>
<dd><p>Bases: <a class="reference internal" href="astropy.io.ascii.core.BaseReader.html#astropy.io.ascii.core.BaseReader" title="astropy.io.ascii.core.BaseReader"><tt class="xref py py-class docutils literal"><span class="pre">astropy.io.ascii.core.BaseReader</span></tt></a></p>
<p>Read a CDS format table. See <a class="reference external" href="http://vizier.u-strasbg.fr/doc/catstd.htx">http://vizier.u-strasbg.fr/doc/catstd.htx</a>.
Example:</p>
<div class="highlight-python"><pre>Table: Table name here
= ==============================================================================
Catalog reference paper
Bibliography info here
================================================================================
ADC_Keywords: Keyword ; Another keyword ; etc
Description:
Catalog description here.
================================================================================
Byte-by-byte Description of file: datafile3.txt
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Index Running identification number
5- 6 I2 h RAh Hour of Right Ascension (J2000)
8- 9 I2 min RAm Minute of Right Ascension (J2000)
11- 15 F5.2 s RAs Second of Right Ascension (J2000)
--------------------------------------------------------------------------------
Note (1): A CDS file can contain sections with various metadata.
Notes can be multiple lines.
Note (2): Another note.
--------------------------------------------------------------------------------
1 03 28 39.09
2 04 18 24.11</pre>
</div>
<p><strong>About parsing the CDS format</strong></p>
<p>The CDS format consists of a table description and the table data. These
can be in separate files as a <tt class="docutils literal"><span class="pre">ReadMe</span></tt> file plus data file(s), or
combined in a single file. Different subsections within the description
are separated by lines of dashes or equal signs (“——” or “======”).
The table which specifies the column information must be preceded by a line
starting with “Byte-by-byte Description of file:”.</p>
<p>In the case where the table description is combined with the data values,
the data must be in the last section and must be preceded by a section
delimiter line (dashes or equal signs only).</p>
<p><strong>Basic usage</strong></p>
<p>Use the <tt class="docutils literal"><span class="pre">ascii.read()</span></tt> function as normal, with an optional <tt class="docutils literal"><span class="pre">readme</span></tt>
parameter indicating the CDS ReadMe file. If not supplied it is assumed that
the header information is at the top of the given table. Examples:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="kn">from</span> <span class="nn">astropy.io</span> <span class="kn">import</span> <span class="n">ascii</span>
<span class="gp">>>> </span><span class="n">table</span> <span class="o">=</span> <span class="n">ascii</span><span class="o">.</span><span class="n">read</span><span class="p">(</span><span class="s">"t/cds.dat"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">table</span> <span class="o">=</span> <span class="n">ascii</span><span class="o">.</span><span class="n">read</span><span class="p">(</span><span class="s">"t/vizier/table1.dat"</span><span class="p">,</span> <span class="n">readme</span><span class="o">=</span><span class="s">"t/vizier/ReadMe"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">table</span> <span class="o">=</span> <span class="n">ascii</span><span class="o">.</span><span class="n">read</span><span class="p">(</span><span class="s">"t/cds/multi/lhs2065.dat"</span><span class="p">,</span> <span class="n">readme</span><span class="o">=</span><span class="s">"t/cds/multi/ReadMe"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">table</span> <span class="o">=</span> <span class="n">ascii</span><span class="o">.</span><span class="n">read</span><span class="p">(</span><span class="s">"t/cds/glob/lmxbrefs.dat"</span><span class="p">,</span> <span class="n">readme</span><span class="o">=</span><span class="s">"t/cds/glob/ReadMe"</span><span class="p">)</span>
</pre></div>
</div>
<p><strong>Using a reader object</strong></p>
<p>When <tt class="docutils literal"><span class="pre">Cds</span></tt> reader object is created with a <tt class="docutils literal"><span class="pre">readme</span></tt> parameter
passed to it at initialization, then when the <tt class="docutils literal"><span class="pre">read</span></tt> method is
executed with a table filename, the header information for the
specified table is taken from the <tt class="docutils literal"><span class="pre">readme</span></tt> file. An
<tt class="docutils literal"><span class="pre">InconsistentTableError</span></tt> is raised if the <tt class="docutils literal"><span class="pre">readme</span></tt> file does not
have header information for the given table.</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="n">readme</span> <span class="o">=</span> <span class="s">"t/vizier/ReadMe"</span>
<span class="gp">>>> </span><span class="n">r</span> <span class="o">=</span> <span class="n">ascii</span><span class="o">.</span><span class="n">get_reader</span><span class="p">(</span><span class="n">ascii</span><span class="o">.</span><span class="n">Cds</span><span class="p">,</span> <span class="n">readme</span><span class="o">=</span><span class="n">readme</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">table</span> <span class="o">=</span> <span class="n">r</span><span class="o">.</span><span class="n">read</span><span class="p">(</span><span class="s">"t/vizier/table1.dat"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="c"># table5.dat has the same ReadMe file</span>
<span class="gp">>>> </span><span class="n">table</span> <span class="o">=</span> <span class="n">r</span><span class="o">.</span><span class="n">read</span><span class="p">(</span><span class="s">"t/vizier/table5.dat"</span><span class="p">)</span>
</pre></div>
</div>
<p>If no <tt class="docutils literal"><span class="pre">readme</span></tt> parameter is specified, then the header
information is assumed to be at the top of the given table.</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="n">r</span> <span class="o">=</span> <span class="n">ascii</span><span class="o">.</span><span class="n">get_reader</span><span class="p">(</span><span class="n">ascii</span><span class="o">.</span><span class="n">Cds</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">table</span> <span class="o">=</span> <span class="n">r</span><span class="o">.</span><span class="n">read</span><span class="p">(</span><span class="s">"t/cds.dat"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="c">#The following gives InconsistentTableError, since no</span>
<span class="gp">>>> </span><span class="c">#readme file was given and table1.dat does not have a header.</span>
<span class="gp">>>> </span><span class="n">table</span> <span class="o">=</span> <span class="n">r</span><span class="o">.</span><span class="n">read</span><span class="p">(</span><span class="s">"t/vizier/table1.dat"</span><span class="p">)</span>
<span class="gt">Traceback (most recent call last):</span>
<span class="c">...</span>
<span class="gr">InconsistentTableError</span>: <span class="n">No CDS section delimiter found</span>
</pre></div>
</div>
<p>Caveats:</p>
<ul class="simple">
<li>Format, Units, and Explanations are available in the <tt class="docutils literal"><span class="pre">Reader.cols</span></tt> attribute.</li>
<li>All of the other metadata defined by this format is ignored.</li>
</ul>
<p>Code contribution to enhance the parsing to include metadata in a Reader.meta
attribute would be welcome.</p>
<p class="rubric">Methods Summary</p>
<table border="1" class="longtable docutils">
<colgroup>
<col width="10%" />
<col width="90%" />
</colgroup>
<tbody valign="top">
<tr class="row-odd"><td><a class="reference internal" href="#astropy.io.ascii.cds.Cds.write" title="astropy.io.ascii.cds.Cds.write"><tt class="xref py py-obj docutils literal"><span class="pre">write</span></tt></a>([table])</td>
<td>Not available for the Cds class (raises NotImplementedError)</td>
</tr>
</tbody>
</table>
<p class="rubric">Methods Documentation</p>
<dl class="method">
<dt id="astropy.io.ascii.cds.Cds.write">
<tt class="descname">write</tt><big>(</big><em>table=None</em><big>)</big><a class="reference external" href="http://github.com/astropy/astropy/tree/v0.2.4/astropy/io/ascii/cds.py#L294" title="Push the Edit button on the next page"><span class="edit-on-github viewcode-link"> [edit on github]</span></a><a class="reference internal" href="../_modules/astropy/io/ascii/cds.html#Cds.write"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#astropy.io.ascii.cds.Cds.write" title="Permalink to this definition">¶</a></dt>
<dd><p>Not available for the Cds class (raises NotImplementedError)</p>
</dd></dl>
</dd></dl>
</div>
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