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<div class="section" id="file-handling-and-convenience-functions">
<h1>File Handling and Convenience Functions<a class="headerlink" href="#file-handling-and-convenience-functions" title="Permalink to this headline">¶</a></h1>
<div class="section" id="open">
<h2><a class="reference internal" href="#astropy.io.fits.open" title="astropy.io.fits.open"><tt class="xref py py-func docutils literal"><span class="pre">open()</span></tt></a><a class="headerlink" href="#open" title="Permalink to this headline">¶</a></h2>
<dl class="function">
<dt id="astropy.io.fits.open">
<tt class="descclassname">astropy.io.fits.</tt><tt class="descname">open</tt><big>(</big><em>name</em>, <em>mode='readonly'</em>, <em>memmap=None</em>, <em>save_backup=False</em>, <em>**kwargs</em><big>)</big><a class="reference external" href="http://github.com/astropy/astropy/tree/v0.2.4/astropy/io/fits.py#L25" title="Push the Edit button on the next page"><span class="edit-on-github viewcode-link"> [edit on github]</span></a><a class="headerlink" href="#astropy.io.fits.open" title="Permalink to this definition">¶</a></dt>
<dd><p>Factory function to open a FITS file and return an <a class="reference internal" href="hdulists.html#astropy.io.fits.HDUList" title="astropy.io.fits.HDUList"><tt class="xref py py-obj docutils literal"><span class="pre">HDUList</span></tt></a> object.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters :</th><td class="field-body"><p class="first"><strong>name</strong> : file path, file object or file-like object</p>
<blockquote>
<div><p>File to be opened.</p>
</div></blockquote>
<p><strong>mode</strong> : str</p>
<blockquote>
<div><p>Open mode, ‘readonly’ (default), ‘update’, ‘append’, ‘denywrite’, or
‘ostream’.</p>
<p>If <tt class="xref py py-obj docutils literal"><span class="pre">name</span></tt> is a file object that is already opened, <tt class="xref py py-obj docutils literal"><span class="pre">mode</span></tt> must
match the mode the file was opened with, copyonwrite (rb),
readonly (rb), update (rb+), append (ab+), ostream (w),
denywrite (rb)).</p>
</div></blockquote>
<p><strong>memmap</strong> : bool</p>
<blockquote>
<div><p>Is memory mapping to be used?</p>
</div></blockquote>
<p><strong>save_backup</strong> : bool</p>
<blockquote>
<div><p>If the file was opened in update or append mode, this ensures that a
backup of the original file is saved before any changes are flushed.
The backup has the same name as the original file with ”.bak” appended.
If “file.bak” already exists then “file.bak.1” is used, and so on.</p>
</div></blockquote>
<p><strong>kwargs</strong> : dict</p>
<blockquote>
<div><p>optional keyword arguments, possible values are:</p>
<ul>
<li><p class="first"><strong>uint</strong> : bool</p>
<blockquote>
<div><p>Interpret signed integer data where <tt class="docutils literal"><span class="pre">BZERO</span></tt> is the
central value and <tt class="docutils literal"><span class="pre">BSCALE</span> <span class="pre">==</span> <span class="pre">1</span></tt> as unsigned integer
data. For example, <tt class="xref py py-obj docutils literal"><span class="pre">int16</span></tt> data with <tt class="docutils literal"><span class="pre">BZERO</span> <span class="pre">=</span> <span class="pre">32768</span></tt>
and <tt class="docutils literal"><span class="pre">BSCALE</span> <span class="pre">=</span> <span class="pre">1</span></tt> would be treated as <tt class="xref py py-obj docutils literal"><span class="pre">uint16</span></tt> data.</p>
<p>Note, for backward compatibility, the kwarg <strong>uint16</strong> may
be used instead. The kwarg was renamed when support was
added for integers of any size.</p>
</div></blockquote>
</li>
<li><p class="first"><strong>ignore_missing_end</strong> : bool</p>
<blockquote>
<div><p>Do not issue an exception when opening a file that is
missing an <tt class="docutils literal"><span class="pre">END</span></tt> card in the last header.</p>
</div></blockquote>
</li>
<li><p class="first"><strong>checksum</strong> : bool, str</p>
<blockquote>
<div><p>If <tt class="xref py py-obj docutils literal"><span class="pre">True</span></tt>, verifies that both <tt class="docutils literal"><span class="pre">DATASUM</span></tt> and
<tt class="docutils literal"><span class="pre">CHECKSUM</span></tt> card values (when present in the HDU header)
match the header and data of all HDU’s in the file. Updates to a
file that already has a checksum will preserve and update the
existing checksums unless this argument is given a value of
‘remove’, in which case the CHECKSUM and DATASUM values are not
checked, and are removed when saving changes to the file.</p>
</div></blockquote>
</li>
<li><p class="first"><strong>disable_image_compression</strong> : bool</p>
<blockquote>
<div><p>If <tt class="xref py py-obj docutils literal"><span class="pre">True</span></tt>, treates compressed image HDU’s like normal
binary table HDU’s.</p>
</div></blockquote>
</li>
<li><p class="first"><strong>do_not_scale_image_data</strong> : bool</p>
<blockquote>
<div><p>If <tt class="xref py py-obj docutils literal"><span class="pre">True</span></tt>, image data is not scaled using BSCALE/BZERO values
when read.</p>
</div></blockquote>
</li>
<li><p class="first"><strong>scale_back</strong> : bool</p>
<blockquote>
<div><p>If <tt class="xref py py-obj docutils literal"><span class="pre">True</span></tt>, when saving changes to a file that contained scaled
image data, restore the data to the original type and reapply the
original BSCALE/BZERO values. This could lead to loss of accuracy
if scaling back to integer values after performing floating point
operations on the data.</p>
</div></blockquote>
</li>
</ul>
</div></blockquote>
</td>
</tr>
<tr class="field-even field"><th class="field-name">Returns :</th><td class="field-body"><p class="first"><strong>hdulist</strong> : an <a class="reference internal" href="hdulists.html#astropy.io.fits.HDUList" title="astropy.io.fits.HDUList"><tt class="xref py py-obj docutils literal"><span class="pre">HDUList</span></tt></a> object</p>
<blockquote class="last">
<div><p><a class="reference internal" href="hdulists.html#astropy.io.fits.HDUList" title="astropy.io.fits.HDUList"><tt class="xref py py-obj docutils literal"><span class="pre">HDUList</span></tt></a> containing all of the header data units in the
file.</p>
</div></blockquote>
</td>
</tr>
</tbody>
</table>
</dd></dl>
</div>
<div class="section" id="writeto">
<h2><a class="reference internal" href="#astropy.io.fits.writeto" title="astropy.io.fits.writeto"><tt class="xref py py-func docutils literal"><span class="pre">writeto()</span></tt></a><a class="headerlink" href="#writeto" title="Permalink to this headline">¶</a></h2>
<dl class="function">
<dt id="astropy.io.fits.writeto">
<tt class="descclassname">astropy.io.fits.</tt><tt class="descname">writeto</tt><big>(</big><em>filename</em>, <em>data</em>, <em>header=None</em>, <em>output_verify='exception'</em>, <em>clobber=False</em>, <em>checksum=False</em><big>)</big><a class="reference external" href="http://github.com/astropy/astropy/tree/v0.2.4/astropy/io/fits.py#L370" title="Push the Edit button on the next page"><span class="edit-on-github viewcode-link"> [edit on github]</span></a><a class="headerlink" href="#astropy.io.fits.writeto" title="Permalink to this definition">¶</a></dt>
<dd><p>Create a new FITS file using the supplied data/header.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters :</th><td class="field-body"><p class="first"><strong>filename</strong> : file path, file object, or file like object</p>
<blockquote>
<div><p>File to write to. If opened, must be opened for append (ab+).</p>
</div></blockquote>
<p><strong>data</strong> : array, record array, or groups data object</p>
<blockquote>
<div><p>data to write to the new file</p>
</div></blockquote>
<p><strong>header</strong> : <a class="reference internal" href="headers.html#astropy.io.fits.Header" title="astropy.io.fits.Header"><tt class="xref py py-obj docutils literal"><span class="pre">Header</span></tt></a> object (optional)</p>
<blockquote>
<div><p>the header associated with <tt class="xref py py-obj docutils literal"><span class="pre">data</span></tt>. If <tt class="xref py py-obj docutils literal"><span class="pre">None</span></tt>, a header
of the appropriate type is created for the supplied data. This
argument is optional.</p>
</div></blockquote>
<p><strong>output_verify</strong> : str</p>
<blockquote>
<div><p>Output verification option. Must be one of <tt class="docutils literal"><span class="pre">"fix"</span></tt>,
<tt class="docutils literal"><span class="pre">"silentfix"</span></tt>, <tt class="docutils literal"><span class="pre">"ignore"</span></tt>, <tt class="docutils literal"><span class="pre">"warn"</span></tt>, or
<tt class="docutils literal"><span class="pre">"exception"</span></tt>. See <a class="reference internal" href="verification.html#verify"><em>Verification options</em></a> for more info.</p>
</div></blockquote>
<p><strong>clobber</strong> : bool (optional)</p>
<blockquote>
<div><p>If <tt class="xref py py-obj docutils literal"><span class="pre">True</span></tt>, and if filename already exists, it will overwrite
the file. Default is <tt class="xref py py-obj docutils literal"><span class="pre">False</span></tt>.</p>
</div></blockquote>
<p><strong>checksum</strong> : bool (optional)</p>
<blockquote class="last">
<div><p>If <tt class="xref py py-obj docutils literal"><span class="pre">True</span></tt>, adds both <tt class="docutils literal"><span class="pre">DATASUM</span></tt> and <tt class="docutils literal"><span class="pre">CHECKSUM</span></tt> cards to the
headers of all HDU’s written to the file.</p>
</div></blockquote>
</td>
</tr>
</tbody>
</table>
</dd></dl>
</div>
<div class="section" id="info">
<h2><a class="reference internal" href="#astropy.io.fits.info" title="astropy.io.fits.info"><tt class="xref py py-func docutils literal"><span class="pre">info()</span></tt></a><a class="headerlink" href="#info" title="Permalink to this headline">¶</a></h2>
<dl class="function">
<dt id="astropy.io.fits.info">
<tt class="descclassname">astropy.io.fits.</tt><tt class="descname">info</tt><big>(</big><em>filename</em>, <em>output=None</em>, <em>**kwargs</em><big>)</big><a class="reference external" href="http://github.com/astropy/astropy/tree/v0.2.4/astropy/io/fits.py#L534" title="Push the Edit button on the next page"><span class="edit-on-github viewcode-link"> [edit on github]</span></a><a class="headerlink" href="#astropy.io.fits.info" title="Permalink to this definition">¶</a></dt>
<dd><p>Print the summary information on a FITS file.</p>
<p>This includes the name, type, length of header, data shape and type
for each extension.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters :</th><td class="field-body"><p class="first"><strong>filename</strong> : file path, file object, or file like object</p>
<blockquote>
<div><p>FITS file to obtain info from. If opened, mode must be one of
the following: rb, rb+, or ab+.</p>
</div></blockquote>
<p><strong>output</strong> : file (optional)</p>
<blockquote>
<div><p>File-like object to output the HDU info to. Outputs to stdout by
default.</p>
</div></blockquote>
<p><strong>kwargs</strong> :</p>
<blockquote class="last">
<div><p>Any additional keyword arguments to be passed to
<a class="reference internal" href="#astropy.io.fits.open" title="astropy.io.fits.open"><tt class="xref py py-obj docutils literal"><span class="pre">astropy.io.fits.open</span></tt></a>.
<em>Note:</em> This function sets <tt class="docutils literal"><span class="pre">ignore_missing_end=True</span></tt> by default.</p>
</div></blockquote>
</td>
</tr>
</tbody>
</table>
</dd></dl>
</div>
<div class="section" id="append">
<h2><a class="reference internal" href="#astropy.io.fits.append" title="astropy.io.fits.append"><tt class="xref py py-func docutils literal"><span class="pre">append()</span></tt></a><a class="headerlink" href="#append" title="Permalink to this headline">¶</a></h2>
<dl class="function">
<dt id="astropy.io.fits.append">
<tt class="descclassname">astropy.io.fits.</tt><tt class="descname">append</tt><big>(</big><em>filename</em>, <em>data</em>, <em>header=None</em>, <em>checksum=False</em>, <em>verify=True</em>, <em>**kwargs</em><big>)</big><a class="reference external" href="http://github.com/astropy/astropy/tree/v0.2.4/astropy/io/fits.py#L409" title="Push the Edit button on the next page"><span class="edit-on-github viewcode-link"> [edit on github]</span></a><a class="headerlink" href="#astropy.io.fits.append" title="Permalink to this definition">¶</a></dt>
<dd><p>Append the header/data to FITS file if filename exists, create if not.</p>
<p>If only <tt class="xref py py-obj docutils literal"><span class="pre">data</span></tt> is supplied, a minimal header is created.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters :</th><td class="field-body"><p class="first"><strong>filename</strong> : file path, file object, or file like object</p>
<blockquote>
<div><p>File to write to. If opened, must be opened for update (rb+)
unless it is a new file, then it must be opened for append
(ab+). A file or <tt class="xref py py-obj docutils literal"><span class="pre">GzipFile</span></tt> object opened for update will be
closed after return.</p>
</div></blockquote>
<p><strong>data</strong> : array, table, or group data object</p>
<blockquote>
<div><p>the new data used for appending</p>
</div></blockquote>
<p><strong>header</strong> : <a class="reference internal" href="headers.html#astropy.io.fits.Header" title="astropy.io.fits.Header"><tt class="xref py py-obj docutils literal"><span class="pre">Header</span></tt></a> object (optional)</p>
<blockquote>
<div><p>The header associated with <tt class="xref py py-obj docutils literal"><span class="pre">data</span></tt>. If <tt class="xref py py-obj docutils literal"><span class="pre">None</span></tt>, an appropriate
header will be created for the data object supplied.</p>
</div></blockquote>
<p><strong>checksum</strong> : bool (optional)</p>
<blockquote>
<div><p>When <tt class="xref py py-obj docutils literal"><span class="pre">True</span></tt> adds both <tt class="docutils literal"><span class="pre">DATASUM</span></tt> and <tt class="docutils literal"><span class="pre">CHECKSUM</span></tt> cards to
the header of the HDU when written to the file.</p>
</div></blockquote>
<p><strong>verify: bool (optional)</strong> :</p>
<blockquote>
<div><p>When <tt class="xref py py-obj docutils literal"><span class="pre">True</span></tt>, the existing FITS file will be read in to verify
it for correctness before appending. When <tt class="xref py py-obj docutils literal"><span class="pre">False</span></tt>, content is
simply appended to the end of the file. Setting <em>verify</em> to
<tt class="xref py py-obj docutils literal"><span class="pre">False</span></tt> can be much faster.</p>
</div></blockquote>
<p><strong>kwargs</strong> :</p>
<blockquote class="last">
<div><p>Any additional keyword arguments to be passed to
<a class="reference internal" href="#astropy.io.fits.open" title="astropy.io.fits.open"><tt class="xref py py-obj docutils literal"><span class="pre">astropy.io.fits.open</span></tt></a>.</p>
</div></blockquote>
</td>
</tr>
</tbody>
</table>
</dd></dl>
</div>
<div class="section" id="update">
<h2><a class="reference internal" href="#astropy.io.fits.update" title="astropy.io.fits.update"><tt class="xref py py-func docutils literal"><span class="pre">update()</span></tt></a><a class="headerlink" href="#update" title="Permalink to this headline">¶</a></h2>
<dl class="function">
<dt id="astropy.io.fits.update">
<tt class="descclassname">astropy.io.fits.</tt><tt class="descname">update</tt><big>(</big><em>filename</em>, <em>data</em>, <em>*args</em>, <em>**kwargs</em><big>)</big><a class="reference external" href="http://github.com/astropy/astropy/tree/v0.2.4/astropy/io/fits.py#L475" title="Push the Edit button on the next page"><span class="edit-on-github viewcode-link"> [edit on github]</span></a><a class="headerlink" href="#astropy.io.fits.update" title="Permalink to this definition">¶</a></dt>
<dd><p>Update the specified extension with the input data/header.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters :</th><td class="field-body"><p class="first"><strong>filename</strong> : file path, file object, or file like object</p>
<blockquote>
<div><p>File to update. If opened, mode must be update (rb+). An
opened file object or <tt class="xref py py-obj docutils literal"><span class="pre">GzipFile</span></tt> object will be closed upon
return.</p>
</div></blockquote>
<p><strong>data</strong> : array, table, or group data object</p>
<blockquote>
<div><p>the new data used for updating</p>
</div></blockquote>
<p><strong>header</strong> : <a class="reference internal" href="headers.html#astropy.io.fits.Header" title="astropy.io.fits.Header"><tt class="xref py py-obj docutils literal"><span class="pre">Header</span></tt></a> object (optional)</p>
<blockquote>
<div><p>The header associated with <tt class="xref py py-obj docutils literal"><span class="pre">data</span></tt>. If <tt class="xref py py-obj docutils literal"><span class="pre">None</span></tt>, an appropriate
header will be created for the data object supplied.</p>
</div></blockquote>
<p><strong>ext, extname, extver</strong> :</p>
<blockquote>
<div><p>The rest of the arguments are flexible: the 3rd argument can
be the header associated with the data. If the 3rd argument
is not a <a class="reference internal" href="headers.html#astropy.io.fits.Header" title="astropy.io.fits.Header"><tt class="xref py py-obj docutils literal"><span class="pre">Header</span></tt></a>, it (and other positional arguments) are
assumed to be the extension specification(s). Header and
extension specs can also be keyword arguments. For example:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="n">update</span><span class="p">(</span><span class="nb">file</span><span class="p">,</span> <span class="n">dat</span><span class="p">,</span> <span class="n">hdr</span><span class="p">,</span> <span class="s">'sci'</span><span class="p">)</span> <span class="c"># update the 'sci' extension</span>
<span class="gp">>>> </span><span class="n">update</span><span class="p">(</span><span class="nb">file</span><span class="p">,</span> <span class="n">dat</span><span class="p">,</span> <span class="mi">3</span><span class="p">)</span> <span class="c"># update the 3rd extension</span>
<span class="gp">>>> </span><span class="n">update</span><span class="p">(</span><span class="nb">file</span><span class="p">,</span> <span class="n">dat</span><span class="p">,</span> <span class="n">hdr</span><span class="p">,</span> <span class="mi">3</span><span class="p">)</span> <span class="c"># update the 3rd extension</span>
<span class="gp">>>> </span><span class="n">update</span><span class="p">(</span><span class="nb">file</span><span class="p">,</span> <span class="n">dat</span><span class="p">,</span> <span class="s">'sci'</span><span class="p">,</span> <span class="mi">2</span><span class="p">)</span> <span class="c"># update the 2nd SCI extension</span>
<span class="gp">>>> </span><span class="n">update</span><span class="p">(</span><span class="nb">file</span><span class="p">,</span> <span class="n">dat</span><span class="p">,</span> <span class="mi">3</span><span class="p">,</span> <span class="n">header</span><span class="o">=</span><span class="n">hdr</span><span class="p">)</span> <span class="c"># update the 3rd extension</span>
<span class="gp">>>> </span><span class="n">update</span><span class="p">(</span><span class="nb">file</span><span class="p">,</span> <span class="n">dat</span><span class="p">,</span> <span class="n">header</span><span class="o">=</span><span class="n">hdr</span><span class="p">,</span> <span class="n">ext</span><span class="o">=</span><span class="mi">5</span><span class="p">)</span> <span class="c"># update the 5th extension</span>
</pre></div>
</div>
</div></blockquote>
<p><strong>kwargs</strong> :</p>
<blockquote class="last">
<div><p>Any additional keyword arguments to be passed to
<a class="reference internal" href="#astropy.io.fits.open" title="astropy.io.fits.open"><tt class="xref py py-obj docutils literal"><span class="pre">astropy.io.fits.open</span></tt></a>.</p>
</div></blockquote>
</td>
</tr>
</tbody>
</table>
</dd></dl>
</div>
<div class="section" id="getdata">
<h2><a class="reference internal" href="#astropy.io.fits.getdata" title="astropy.io.fits.getdata"><tt class="xref py py-func docutils literal"><span class="pre">getdata()</span></tt></a><a class="headerlink" href="#getdata" title="Permalink to this headline">¶</a></h2>
<dl class="function">
<dt id="astropy.io.fits.getdata">
<tt class="descclassname">astropy.io.fits.</tt><tt class="descname">getdata</tt><big>(</big><em>filename</em>, <em>*args</em>, <em>**kwargs</em><big>)</big><a class="reference external" href="http://github.com/astropy/astropy/tree/v0.2.4/astropy/io/fits.py#L109" title="Push the Edit button on the next page"><span class="edit-on-github viewcode-link"> [edit on github]</span></a><a class="headerlink" href="#astropy.io.fits.getdata" title="Permalink to this definition">¶</a></dt>
<dd><p>Get the data from an extension of a FITS file (and optionally the
header).</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters :</th><td class="field-body"><p class="first"><strong>filename</strong> : file path, file object, or file like object</p>
<blockquote>
<div><p>File to get data from. If opened, mode must be one of the
following rb, rb+, or ab+.</p>
</div></blockquote>
<p><strong>ext</strong> :</p>
<blockquote>
<div><p>The rest of the arguments are for extension specification.
They are flexible and are best illustrated by examples.</p>
<p>No extra arguments implies the primary header:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="n">getdata</span><span class="p">(</span><span class="s">'in.fits'</span><span class="p">)</span>
</pre></div>
</div>
<p>By extension number:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="n">getdata</span><span class="p">(</span><span class="s">'in.fits'</span><span class="p">,</span> <span class="mi">0</span><span class="p">)</span> <span class="c"># the primary header</span>
<span class="gp">>>> </span><span class="n">getdata</span><span class="p">(</span><span class="s">'in.fits'</span><span class="p">,</span> <span class="mi">2</span><span class="p">)</span> <span class="c"># the second extension</span>
<span class="gp">>>> </span><span class="n">getdata</span><span class="p">(</span><span class="s">'in.fits'</span><span class="p">,</span> <span class="n">ext</span><span class="o">=</span><span class="mi">2</span><span class="p">)</span> <span class="c"># the second extension</span>
</pre></div>
</div>
<p>By name, i.e., <tt class="docutils literal"><span class="pre">EXTNAME</span></tt> value (if unique):</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="n">getdata</span><span class="p">(</span><span class="s">'in.fits'</span><span class="p">,</span> <span class="s">'sci'</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">getdata</span><span class="p">(</span><span class="s">'in.fits'</span><span class="p">,</span> <span class="n">extname</span><span class="o">=</span><span class="s">'sci'</span><span class="p">)</span> <span class="c"># equivalent</span>
</pre></div>
</div>
<p>Note <tt class="docutils literal"><span class="pre">EXTNAME</span></tt> values are not case sensitive</p>
<p>By combination of <tt class="docutils literal"><span class="pre">EXTNAME</span></tt> and EXTVER`` as separate
arguments or as a tuple:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="n">getdata</span><span class="p">(</span><span class="s">'in.fits'</span><span class="p">,</span> <span class="s">'sci'</span><span class="p">,</span> <span class="mi">2</span><span class="p">)</span> <span class="c"># EXTNAME='SCI' & EXTVER=2</span>
<span class="gp">>>> </span><span class="n">getdata</span><span class="p">(</span><span class="s">'in.fits'</span><span class="p">,</span> <span class="n">extname</span><span class="o">=</span><span class="s">'sci'</span><span class="p">,</span> <span class="n">extver</span><span class="o">=</span><span class="mi">2</span><span class="p">)</span> <span class="c"># equivalent</span>
<span class="gp">>>> </span><span class="n">getdata</span><span class="p">(</span><span class="s">'in.fits'</span><span class="p">,</span> <span class="p">(</span><span class="s">'sci'</span><span class="p">,</span> <span class="mi">2</span><span class="p">))</span> <span class="c"># equivalent</span>
</pre></div>
</div>
<p>Ambiguous or conflicting specifications will raise an exception:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="n">getdata</span><span class="p">(</span><span class="s">'in.fits'</span><span class="p">,</span> <span class="n">ext</span><span class="o">=</span><span class="p">(</span><span class="s">'sci'</span><span class="p">,</span><span class="mi">1</span><span class="p">),</span> <span class="n">extname</span><span class="o">=</span><span class="s">'err'</span><span class="p">,</span> <span class="n">extver</span><span class="o">=</span><span class="mi">2</span><span class="p">)</span>
</pre></div>
</div>
</div></blockquote>
<p><strong>header</strong> : bool (optional)</p>
<blockquote>
<div><p>If <tt class="xref py py-obj docutils literal"><span class="pre">True</span></tt>, return the data and the header of the specified HDU as a
tuple.</p>
</div></blockquote>
<p><strong>lower, upper</strong> : bool (optional)</p>
<blockquote>
<div><p>If <tt class="xref py py-obj docutils literal"><span class="pre">lower</span></tt> or <tt class="xref py py-obj docutils literal"><span class="pre">upper</span></tt> are <tt class="xref py py-obj docutils literal"><span class="pre">True</span></tt>, the field names in the
returned data object will be converted to lower or upper case,
respectively.</p>
</div></blockquote>
<p><strong>view</strong> : ndarray (optional)</p>
<blockquote>
<div><p>When given, the data will be turned wrapped in the given ndarray
subclass by calling:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="n">data</span><span class="o">.</span><span class="n">view</span><span class="p">(</span><span class="n">view</span><span class="p">)</span>
</pre></div>
</div>
</div></blockquote>
<p><strong>kwargs</strong> :</p>
<blockquote>
<div><p>Any additional keyword arguments to be passed to
<a class="reference internal" href="#astropy.io.fits.open" title="astropy.io.fits.open"><tt class="xref py py-obj docutils literal"><span class="pre">astropy.io.fits.open</span></tt></a>.</p>
</div></blockquote>
</td>
</tr>
<tr class="field-even field"><th class="field-name">Returns :</th><td class="field-body"><p class="first"><strong>array</strong> : array, record array or groups data object</p>
<blockquote class="last">
<div><p>Type depends on the type of the extension being referenced.</p>
<p>If the optional keyword <tt class="xref py py-obj docutils literal"><span class="pre">header</span></tt> is set to <tt class="xref py py-obj docutils literal"><span class="pre">True</span></tt>, this
function will return a (<tt class="xref py py-obj docutils literal"><span class="pre">data</span></tt>, <tt class="xref py py-obj docutils literal"><span class="pre">header</span></tt>) tuple.</p>
</div></blockquote>
</td>
</tr>
</tbody>
</table>
</dd></dl>
</div>
<div class="section" id="getheader">
<h2><a class="reference internal" href="#astropy.io.fits.getheader" title="astropy.io.fits.getheader"><tt class="xref py py-func docutils literal"><span class="pre">getheader()</span></tt></a><a class="headerlink" href="#getheader" title="Permalink to this headline">¶</a></h2>
<dl class="function">
<dt id="astropy.io.fits.getheader">
<tt class="descclassname">astropy.io.fits.</tt><tt class="descname">getheader</tt><big>(</big><em>filename</em>, <em>*args</em>, <em>**kwargs</em><big>)</big><a class="reference external" href="http://github.com/astropy/astropy/tree/v0.2.4/astropy/io/fits.py#L78" title="Push the Edit button on the next page"><span class="edit-on-github viewcode-link"> [edit on github]</span></a><a class="headerlink" href="#astropy.io.fits.getheader" title="Permalink to this definition">¶</a></dt>
<dd><p>Get the header from an extension of a FITS file.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters :</th><td class="field-body"><p class="first"><strong>filename</strong> : file path, file object, or file like object</p>
<blockquote>
<div><p>File to get header from. If an opened file object, its mode
must be one of the following rb, rb+, or ab+).</p>
</div></blockquote>
<p><strong>ext, extname, extver</strong> :</p>
<blockquote>
<div><p>The rest of the arguments are for extension specification. See the
<a class="reference internal" href="#astropy.io.fits.getdata" title="astropy.io.fits.getdata"><tt class="xref py py-obj docutils literal"><span class="pre">getdata</span></tt></a> documentation for explanations/examples.</p>
</div></blockquote>
<p><strong>kwargs</strong> :</p>
<blockquote>
<div><p>Any additional keyword arguments to be passed to
<a class="reference internal" href="#astropy.io.fits.open" title="astropy.io.fits.open"><tt class="xref py py-obj docutils literal"><span class="pre">astropy.io.fits.open</span></tt></a>.</p>
</div></blockquote>
</td>
</tr>
<tr class="field-even field"><th class="field-name">Returns :</th><td class="field-body"><p class="first last"><strong>header</strong> : <a class="reference internal" href="headers.html#astropy.io.fits.Header" title="astropy.io.fits.Header"><tt class="xref py py-obj docutils literal"><span class="pre">Header</span></tt></a> object</p>
</td>
</tr>
</tbody>
</table>
</dd></dl>
</div>
<div class="section" id="getval">
<h2><a class="reference internal" href="#astropy.io.fits.getval" title="astropy.io.fits.getval"><tt class="xref py py-func docutils literal"><span class="pre">getval()</span></tt></a><a class="headerlink" href="#getval" title="Permalink to this headline">¶</a></h2>
<dl class="function">
<dt id="astropy.io.fits.getval">
<tt class="descclassname">astropy.io.fits.</tt><tt class="descname">getval</tt><big>(</big><em>filename</em>, <em>keyword</em>, <em>*args</em>, <em>**kwargs</em><big>)</big><a class="reference external" href="http://github.com/astropy/astropy/tree/v0.2.4/astropy/io/fits.py#L227" title="Push the Edit button on the next page"><span class="edit-on-github viewcode-link"> [edit on github]</span></a><a class="headerlink" href="#astropy.io.fits.getval" title="Permalink to this definition">¶</a></dt>
<dd><p>Get a keyword’s value from a header in a FITS file.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters :</th><td class="field-body"><p class="first"><strong>filename</strong> : file path, file object, or file like object</p>
<blockquote>
<div><p>Name of the FITS file, or file object (if opened, mode must be
one of the following rb, rb+, or ab+).</p>
</div></blockquote>
<p><strong>keyword</strong> : str</p>
<blockquote>
<div><p>Keyword name</p>
</div></blockquote>
<p><strong>ext, extname, extver</strong> :</p>
<blockquote>
<div><p>The rest of the arguments are for extension specification.
See <a class="reference internal" href="#astropy.io.fits.getdata" title="astropy.io.fits.getdata"><tt class="xref py py-obj docutils literal"><span class="pre">getdata</span></tt></a> for explanations/examples.</p>
</div></blockquote>
<p><strong>kwargs</strong> :</p>
<blockquote>
<div><p>Any additional keyword arguments to be passed to
<a class="reference internal" href="#astropy.io.fits.open" title="astropy.io.fits.open"><tt class="xref py py-obj docutils literal"><span class="pre">astropy.io.fits.open</span></tt></a>.
<em>Note:</em> This function automatically specifies <tt class="docutils literal"><span class="pre">do_not_scale_image_data</span>
<span class="pre">=</span> <span class="pre">True</span></tt> when opening the file so that values can be retrieved from the
unmodified header.</p>
</div></blockquote>
</td>
</tr>
<tr class="field-even field"><th class="field-name">Returns :</th><td class="field-body"><p class="first last"><strong>keyword value</strong> : string, integer, or float</p>
</td>
</tr>
</tbody>
</table>
</dd></dl>
</div>
<div class="section" id="setval">
<h2><a class="reference internal" href="#astropy.io.fits.setval" title="astropy.io.fits.setval"><tt class="xref py py-func docutils literal"><span class="pre">setval()</span></tt></a><a class="headerlink" href="#setval" title="Permalink to this headline">¶</a></h2>
<dl class="function">
<dt id="astropy.io.fits.setval">
<tt class="descclassname">astropy.io.fits.</tt><tt class="descname">setval</tt><big>(</big><em>filename</em>, <em>keyword</em>, <em>*args</em>, <em>**kwargs</em><big>)</big><a class="reference external" href="http://github.com/astropy/astropy/tree/v0.2.4/astropy/io/fits.py#L263" title="Push the Edit button on the next page"><span class="edit-on-github viewcode-link"> [edit on github]</span></a><a class="headerlink" href="#astropy.io.fits.setval" title="Permalink to this definition">¶</a></dt>
<dd><p>Set a keyword’s value from a header in a FITS file.</p>
<p>If the keyword already exists, it’s value/comment will be updated.
If it does not exist, a new card will be created and it will be
placed before or after the specified location. If no <tt class="xref py py-obj docutils literal"><span class="pre">before</span></tt> or
<tt class="xref py py-obj docutils literal"><span class="pre">after</span></tt> is specified, it will be appended at the end.</p>
<p>When updating more than one keyword in a file, this convenience
function is a much less efficient approach compared with opening
the file for update, modifying the header, and closing the file.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters :</th><td class="field-body"><p class="first"><strong>filename</strong> : file path, file object, or file like object</p>
<blockquote>
<div><p>Name of the FITS file, or file object If opened, mode must be
update (rb+). An opened file object or <tt class="xref py py-obj docutils literal"><span class="pre">GzipFile</span></tt> object will
be closed upon return.</p>
</div></blockquote>
<p><strong>keyword</strong> : str</p>
<blockquote>
<div><p>Keyword name</p>
</div></blockquote>
<p><strong>value</strong> : str, int, float (optional)</p>
<blockquote>
<div><p>Keyword value (default: <tt class="xref py py-obj docutils literal"><span class="pre">None</span></tt>, meaning don’t modify)</p>
</div></blockquote>
<p><strong>comment</strong> : str (optional)</p>
<blockquote>
<div><p>Keyword comment, (default: <tt class="xref py py-obj docutils literal"><span class="pre">None</span></tt>, meaning don’t modify)</p>
</div></blockquote>
<p><strong>before</strong> : str, int (optional)</p>
<blockquote>
<div><p>Name of the keyword, or index of the card before which the new card
will be placed. The argument <tt class="xref py py-obj docutils literal"><span class="pre">before</span></tt> takes precedence over <tt class="xref py py-obj docutils literal"><span class="pre">after</span></tt> if
both are specified (default: <tt class="xref py py-obj docutils literal"><span class="pre">None</span></tt>).</p>
</div></blockquote>
<p><strong>after</strong> : str, int (optional)</p>
<blockquote>
<div><p>Name of the keyword, or index of the card after which the new card will
be placed. (default: <tt class="xref py py-obj docutils literal"><span class="pre">None</span></tt>).</p>
</div></blockquote>
<p><strong>savecomment</strong> : bool (optional)</p>
<blockquote>
<div><p>When <tt class="xref py py-obj docutils literal"><span class="pre">True</span></tt>, preserve the current comment for an existing keyword. The
argument <tt class="xref py py-obj docutils literal"><span class="pre">savecomment</span></tt> takes precedence over <tt class="xref py py-obj docutils literal"><span class="pre">comment</span></tt> if both
specified. If <tt class="xref py py-obj docutils literal"><span class="pre">comment</span></tt> is not specified then the current comment will
automatically be preserved (default: <tt class="xref py py-obj docutils literal"><span class="pre">False</span></tt>).</p>
</div></blockquote>
<p><strong>ext, extname, extver</strong> :</p>
<blockquote>
<div><p>The rest of the arguments are for extension specification.
See <a class="reference internal" href="#astropy.io.fits.getdata" title="astropy.io.fits.getdata"><tt class="xref py py-obj docutils literal"><span class="pre">getdata</span></tt></a> for explanations/examples.</p>
</div></blockquote>
<p><strong>kwargs</strong> :</p>
<blockquote class="last">
<div><p>Any additional keyword arguments to be passed to
<a class="reference internal" href="#astropy.io.fits.open" title="astropy.io.fits.open"><tt class="xref py py-obj docutils literal"><span class="pre">astropy.io.fits.open</span></tt></a>.
<em>Note:</em> This function automatically specifies <tt class="docutils literal"><span class="pre">do_not_scale_image_data</span>
<span class="pre">=</span> <span class="pre">True</span></tt> when opening the file so that values can be retrieved from the
unmodified header.</p>
</div></blockquote>
</td>
</tr>
</tbody>
</table>
</dd></dl>
</div>
<div class="section" id="delval">
<h2><a class="reference internal" href="#astropy.io.fits.delval" title="astropy.io.fits.delval"><tt class="xref py py-func docutils literal"><span class="pre">delval()</span></tt></a><a class="headerlink" href="#delval" title="Permalink to this headline">¶</a></h2>
<dl class="function">
<dt id="astropy.io.fits.delval">
<tt class="descclassname">astropy.io.fits.</tt><tt class="descname">delval</tt><big>(</big><em>filename</em>, <em>keyword</em>, <em>*args</em>, <em>**kwargs</em><big>)</big><a class="reference external" href="http://github.com/astropy/astropy/tree/v0.2.4/astropy/io/fits.py#L335" title="Push the Edit button on the next page"><span class="edit-on-github viewcode-link"> [edit on github]</span></a><a class="headerlink" href="#astropy.io.fits.delval" title="Permalink to this definition">¶</a></dt>
<dd><p>Delete all instances of keyword from a header in a FITS file.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters :</th><td class="field-body"><p class="first"><strong>filename</strong> : file path, file object, or file like object</p>
<blockquote>
<div><p>Name of the FITS file, or file object If opened, mode must be
update (rb+). An opened file object or <tt class="xref py py-obj docutils literal"><span class="pre">GzipFile</span></tt> object will
be closed upon return.</p>
</div></blockquote>
<p><strong>keyword</strong> : str, int</p>
<blockquote>
<div><p>Keyword name or index</p>
</div></blockquote>
<p><strong>ext, extname, extver</strong> :</p>
<blockquote>
<div><p>The rest of the arguments are for extension specification.
See <a class="reference internal" href="#astropy.io.fits.getdata" title="astropy.io.fits.getdata"><tt class="xref py py-obj docutils literal"><span class="pre">getdata</span></tt></a> for explanations/examples.</p>
</div></blockquote>
<p><strong>kwargs</strong> :</p>
<blockquote class="last">
<div><p>Any additional keyword arguments to be passed to
<a class="reference internal" href="#astropy.io.fits.open" title="astropy.io.fits.open"><tt class="xref py py-obj docutils literal"><span class="pre">astropy.io.fits.open</span></tt></a>.
<em>Note:</em> This function automatically specifies <tt class="docutils literal"><span class="pre">do_not_scale_image_data</span>
<span class="pre">=</span> <span class="pre">True</span></tt> when opening the file so that values can be retrieved from the
unmodified header.</p>
</div></blockquote>
</td>
</tr>
</tbody>
</table>
</dd></dl>
</div>
</div>
</div>
</div>
</div>
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<ul>
<li><a class="reference internal" href="#">File Handling and Convenience Functions</a><ul>
<li><a class="reference internal" href="#open"><tt class="docutils literal"><span class="pre">open()</span></tt></a></li>
<li><a class="reference internal" href="#writeto"><tt class="docutils literal"><span class="pre">writeto()</span></tt></a></li>
<li><a class="reference internal" href="#info"><tt class="docutils literal"><span class="pre">info()</span></tt></a></li>
<li><a class="reference internal" href="#append"><tt class="docutils literal"><span class="pre">append()</span></tt></a></li>
<li><a class="reference internal" href="#update"><tt class="docutils literal"><span class="pre">update()</span></tt></a></li>
<li><a class="reference internal" href="#getdata"><tt class="docutils literal"><span class="pre">getdata()</span></tt></a></li>
<li><a class="reference internal" href="#getheader"><tt class="docutils literal"><span class="pre">getheader()</span></tt></a></li>
<li><a class="reference internal" href="#getval"><tt class="docutils literal"><span class="pre">getval()</span></tt></a></li>
<li><a class="reference internal" href="#setval"><tt class="docutils literal"><span class="pre">setval()</span></tt></a></li>
<li><a class="reference internal" href="#delval"><tt class="docutils literal"><span class="pre">delval()</span></tt></a></li>
</ul>
</li>
</ul>
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