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<a href="pygrib-module.html">Module pygrib</a> ::
Class index
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<!-- ==================== TYPE DESCRIPTION ==================== -->
<h1 class="epydoc">type index</h1><p class="nomargin-top"></p>
<pre class="base-tree">
object --+
|
<strong class="uidshort">index</strong>
</pre>
<hr />
<p>index(filename, *args)</p>
<p>returns grib index object given GRIB filename indexed by keys given in
*args. The <a href="pygrib.index-class.html#select"
class="link">select</a> or <a href="pygrib.index-class.html#__call__"
class="link">__call__</a> method can then be used to selected grib
messages based on specified values of indexed keys. Unlike <a
href="pygrib.open-class.html#select" class="link">open.select</a>,
containers or callables cannot be used to select multiple key values.
However, using <a href="pygrib.index-class.html#select"
class="link">index.select</a> is much faster than <a
href="pygrib.open-class.html#select" class="link">open.select</a>.</p>
<p><b>Warning</b>: Searching for data within multi-field grib messages
does not work using an index (and is not supported by the <a
href="https://software.ecmwf.int/wiki/display/GRIB/Home"
target="_top">GRIB API</a> library). NCEP often puts u and v winds
together in a single multi-field grib message. You will get incorrect
results if you try to use an index to find data in these messages. Use
the slower, but more robust <a href="pygrib.open-class.html#select"
class="link">open.select</a> in this case.</p>
<p>If no key are given (i.e. *args is empty), it is assumed the filename
represents a previously saved index (created using the
<code>grib_index_build</code> tool or <a
href="pygrib.index-class.html#write" class="link">index.write</a>)
instead of a GRIB file.</p>
<p>Example usage:</p>
<pre class="py-doctest">
<span class="py-prompt">>>> </span><span class="py-keyword">import</span> pygrib
<span class="py-prompt">>>> </span>grbindx=pygrib.index(<span class="py-string">'sampledata/gfs.grb'</span>,<span class="py-string">'shortName'</span>,<span class="py-string">'typeOfLevel'</span>,<span class="py-string">'level'</span>)
<span class="py-prompt">>>> </span>selected_grbs=grbindx.select(shortName=<span class="py-string">'gh'</span>,typeOfLevel=<span class="py-string">'isobaricInhPa'</span>,level=500)
<span class="py-prompt">>>> </span><span class="py-keyword">for</span> grb <span class="py-keyword">in</span> selected_grbs:
<span class="py-prompt">>>> </span> grb
<span class="py-output">1:Geopotential height:gpm (instant):regular_ll:isobaricInhPa:level 500 Pa:fcst time 72 hrs:from 200412091200:lo res cntl fcst</span>
<span class="py-output"></span><span class="py-prompt">>>> </span><span class="py-comment"># __call__ method does same thing as select</span>
<span class="py-prompt">>>> </span>selected_grbs=grbindx(shortName=<span class="py-string">'u'</span>,typeOfLevel=<span class="py-string">'isobaricInhPa'</span>,level=250)
<span class="py-prompt">>>> </span><span class="py-keyword">for</span> grb <span class="py-keyword">in</span> selected_grbs:
<span class="py-prompt">>>> </span> grb
<span class="py-output">1:u-component of wind:m s**-1 (instant):regular_ll:isobaricInhPa:level 250 Pa:fcst time 72 hrs:from 200412091200:lo res cntl fcst</span>
<span class="py-output"></span><span class="py-prompt">>>> </span>grbindx.write(<span class="py-string">'gfs.grb.idx'</span>) <span class="py-comment"># save index to a file</span>
<span class="py-prompt">>>> </span>grbindx.close()
<span class="py-prompt">>>> </span>grbindx = pygrib.index(<span class="py-string">'gfs.grb.idx'</span>) <span class="py-comment"># re-open index (no keys specified)</span>
<span class="py-prompt">>>> </span><span class="py-keyword">for</span> grb <span class="py-keyword">in</span> selected_grbs:
<span class="py-prompt">>>> </span> grb
<span class="py-output">1:u-component of wind:m s**-1 (instant):regular_ll:isobaricInhPa:level 250 Pa:fcst time 72 hrs:from 200412091200:lo res cntl fcst</span></pre>
<!-- ==================== INSTANCE METHODS ==================== -->
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<span class="table-header">Instance Methods</span></td>
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<td width="15%" align="right" valign="top" class="summary">
<span class="summary-type"> </span>
</td><td class="summary">
<table width="100%" cellpadding="0" cellspacing="0" border="0">
<tr>
<td><span class="summary-sig"><a name="__call__"></a><span class="summary-sig-name">__call__</span>(<span class="summary-sig-arg">...</span>)</span><br />
same as <a href="pygrib.index-class.html#select"
class="link">select</a></td>
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</td>
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<td width="15%" align="right" valign="top" class="summary">
<span class="summary-type"> </span>
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<table width="100%" cellpadding="0" cellspacing="0" border="0">
<tr>
<td><span class="summary-sig"><a href="pygrib.index-class.html#__init__" class="summary-sig-name">__init__</a>(<span class="summary-sig-arg">filename</span>,
<span class="summary-sig-arg">*args</span>)</span><br />
x.__init__(...) initializes x; see help(type(x)) for signature</td>
<td align="right" valign="top">
</td>
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</td>
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<td width="15%" align="right" valign="top" class="summary">
<span class="summary-type">a new object with type S, a subtype of T</span>
</td><td class="summary">
<table width="100%" cellpadding="0" cellspacing="0" border="0">
<tr>
<td><span class="summary-sig"><a href="pygrib.index-class.html#__new__" class="summary-sig-name">__new__</a>(<span class="summary-sig-arg">T</span>,
<span class="summary-sig-arg">S</span>,
<span class="summary-sig-arg">...</span>)</span></td>
<td align="right" valign="top">
</td>
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<td width="15%" align="right" valign="top" class="summary">
<span class="summary-type"> </span>
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<tr>
<td><span class="summary-sig"><a name="close"></a><span class="summary-sig-name">close</span>()</span><br />
deallocate C structures associated with class instance</td>
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</td>
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</td>
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<td width="15%" align="right" valign="top" class="summary">
<span class="summary-type"> </span>
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<tr>
<td><span class="summary-sig"><a href="pygrib.index-class.html#select" class="summary-sig-name">select</a>(<span class="summary-sig-arg">**kwargs</span>)</span><br />
return a list of <a href="pygrib.gribmessage-class.html"
class="link">gribmessage</a> instances from grib index object
corresponding to specific values of indexed keys (given by kwargs).</td>
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</td>
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<td width="15%" align="right" valign="top" class="summary">
<span class="summary-type"> </span>
</td><td class="summary">
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<tr>
<td><span class="summary-sig"><a name="write"></a><span class="summary-sig-name">write</span>(<span class="summary-sig-arg">filename</span>)</span><br />
save grib index to file</td>
<td align="right" valign="top">
</td>
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<!-- ==================== INSTANCE VARIABLES ==================== -->
<a name="section-InstanceVariables"></a>
<table class="summary" border="1" cellpadding="3"
cellspacing="0" width="100%" bgcolor="white">
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<span class="table-header">Instance Variables</span></td>
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<td width="15%" align="right" valign="top" class="summary">
<span class="summary-type"> </span>
</td><td class="summary">
<a name="keys"></a><span class="summary-name">keys</span><br />
list of strings containing keys used in the index.
</td>
</tr>
<tr>
<td width="15%" align="right" valign="top" class="summary">
<span class="summary-type"> </span>
</td><td class="summary">
<a href="pygrib.index-class.html#types" class="summary-name">types</a><br />
if keys are typed, this list contains the type declarations
(<code>l</code>, <code>s</code> or <code>d</code>).
</td>
</tr>
</table>
<!-- ==================== PROPERTIES ==================== -->
<a name="section-Properties"></a>
<table class="summary" border="1" cellpadding="3"
cellspacing="0" width="100%" bgcolor="white">
<tr bgcolor="#70b0f0" class="table-header">
<td align="left" colspan="2" class="table-header">
<span class="table-header">Properties</span></td>
</tr>
<tr>
<td width="15%" align="right" valign="top" class="summary">
<span class="summary-type"> </span>
</td><td class="summary">
<a name="name"></a><span class="summary-name">name</span>
</td>
</tr>
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<!-- ==================== METHOD DETAILS ==================== -->
<a name="section-MethodDetails"></a>
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<span class="table-header">Method Details</span></td>
</tr>
</table>
<a name="__init__"></a>
<div>
<table class="details" border="1" cellpadding="3"
cellspacing="0" width="100%" bgcolor="white">
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<table width="100%" cellpadding="0" cellspacing="0" border="0">
<tr valign="top"><td>
<h3 class="epydoc"><span class="sig"><span class="sig-name">__init__</span>(<span class="sig-arg">filename</span>,
<span class="sig-arg">*args</span>)</span>
<br /><em class="fname">(Constructor)</em>
</h3>
</td><td align="right" valign="top"
>
</td>
</tr></table>
<p>x.__init__(...) initializes x; see help(type(x)) for signature</p>
<dl class="fields">
<dt>Overrides:
object.__init__
</dt>
</dl>
</td></tr></table>
</div>
<a name="__new__"></a>
<div>
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cellspacing="0" width="100%" bgcolor="white">
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<table width="100%" cellpadding="0" cellspacing="0" border="0">
<tr valign="top"><td>
<h3 class="epydoc"><span class="sig"><span class="sig-name">__new__</span>(<span class="sig-arg">T</span>,
<span class="sig-arg">S</span>,
<span class="sig-arg">...</span>)</span>
</h3>
</td><td align="right" valign="top"
>
</td>
</tr></table>
<dl class="fields">
<dt>Returns: a new object with type S, a subtype of T</dt>
<dt>Overrides:
object.__new__
</dt>
</dl>
</td></tr></table>
</div>
<a name="select"></a>
<div>
<table class="details" border="1" cellpadding="3"
cellspacing="0" width="100%" bgcolor="white">
<tr><td>
<table width="100%" cellpadding="0" cellspacing="0" border="0">
<tr valign="top"><td>
<h3 class="epydoc"><span class="sig"><span class="sig-name">select</span>(<span class="sig-arg">**kwargs</span>)</span>
</h3>
</td><td align="right" valign="top"
>
</td>
</tr></table>
<p>return a list of <a href="pygrib.gribmessage-class.html"
class="link">gribmessage</a> instances from grib index object
corresponding to specific values of indexed keys (given by kwargs).
Unlike <a href="pygrib.open-class.html#select"
class="link">open.select</a>, containers or callables cannot be used to
select multiple key values. However, using <a
href="pygrib.index-class.html#select" class="link">index.select</a> is
much faster than <a href="pygrib.open-class.html#select"
class="link">open.select</a>.</p>
<p>Example usage:</p>
<pre class="py-doctest">
<span class="py-prompt">>>> </span><span class="py-keyword">import</span> pygrib
<span class="py-prompt">>>> </span>grbindx=pygrib.index(<span class="py-string">'sampledata/gfs.grb'</span>,<span class="py-string">'shortName'</span>,<span class="py-string">'typeOfLevel'</span>,<span class="py-string">'level'</span>)
<span class="py-prompt">>>> </span>selected_grbs=grbindx.select(shortName=<span class="py-string">'gh'</span>,typeOfLevel=<span class="py-string">'isobaricInhPa'</span>,level=500)
<span class="py-prompt">>>> </span><span class="py-keyword">for</span> grb <span class="py-keyword">in</span> selected_grbs:
<span class="py-prompt">>>> </span> grb
<span class="py-output">1:Geopotential height:gpm (instant):regular_ll:isobaricInhPa:level 500 Pa:fcst time 72 hrs:from 200412091200:lo res cntl fcst</span>
<span class="py-output"></span><span class="py-prompt">>>> </span><span class="py-comment"># __call__ method does same thing as select</span>
<span class="py-prompt">>>> </span>selected_grbs=grbindx(shortName=<span class="py-string">'u'</span>,typeOfLevel=<span class="py-string">'isobaricInhPa'</span>,level=250)
<span class="py-prompt">>>> </span><span class="py-keyword">for</span> grb <span class="py-keyword">in</span> selected_grbs:
<span class="py-prompt">>>> </span> grb
<span class="py-output">1:u-component of wind:m s**-1 (instant):regular_ll:isobaricInhPa:level 250 Pa:fcst time 72 hrs:from 200412091200:lo res cntl fcst</span>
<span class="py-output"></span><span class="py-prompt">>>> </span>grbindx.close()</pre>
<dl class="fields">
</dl>
</td></tr></table>
</div>
<br />
<!-- ==================== INSTANCE VARIABLE DETAILS ==================== -->
<a name="section-InstanceVariableDetails"></a>
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cellspacing="0" width="100%" bgcolor="white">
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<td align="left" colspan="2" class="table-header">
<span class="table-header">Instance Variable Details</span></td>
</tr>
</table>
<a name="types"></a>
<div>
<table class="details" border="1" cellpadding="3"
cellspacing="0" width="100%" bgcolor="white">
<tr><td>
<h3 class="epydoc">types</h3>
if keys are typed, this list contains the type declarations
(<code>l</code>, <code>s</code> or <code>d</code>). Type declarations are
specified by appending to the key name (i.e. <code>level:l</code> will
search for values of <code>level</code> that are longs).
<dl class="fields">
</dl>
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