docs/dev/c_glib/parquet-glib/method.ArrowFileReader.read_row_group.html - arrow-site - Git at Google

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         <p>API Version: 1.0</p>

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   <h5>Type</h5>
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     <a href="class.ArrowFileReader.html">ArrowFileReader</a>
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     <a class="method" href="method.ArrowFileReader.get_metadata.html">get_metadata</a>

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     <a class="method current" href="method.ArrowFileReader.read_row_group.html">read_row_group</a>

     <a class="method" href="method.ArrowFileReader.read_table.html">read_table</a>

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     <h3>Method</h3>
     <h1><a href="index.html">Parquet</a><span class="sep"></span><a href="class.ArrowFileReader.html">ArrowFileReader</a><span class="sep"></span>read_row_group</h1>
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     <div class="docblock">
       <p><span class="emblem available">since: 1.0.0</span></p>
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       <h4 style="display:flex;" id="declaration">
         Declaration
         <a class="anchor" href="#declaration"></a>

         <a class="srclink" title="go to source location" href="https://github.com/apache/arrow/blob/main/c_glib/parquet-glib/arrow-file-reader.h#L52">[src]</a>

       </h4>

       <div class="docblock c-decl">
         <pre><code><div class="highlight"><pre><span></span><span class="n">GArrowTable</span><span class="o">*</span>
 <span class="n">gparquet_arrow_file_reader_read_row_group</span><span class="w"> </span><span class="p">(</span>
 <span class="w">  </span><span class="n">GParquetArrowFileReader</span><span class="o">*</span><span class="w"> </span><span class="n">reader</span><span class="p">,</span>
 <span class="w">  </span><span class="n">gint</span><span class="w"> </span><span class="n">row_group_index</span><span class="p">,</span>
 <span class="w">  </span><span class="n">gint</span><span class="o">*</span><span class="w"> </span><span class="n">column_indices</span><span class="p">,</span>
 <span class="w">  </span><span class="n">gsize</span><span class="w"> </span><span class="n">n_column_indices</span><span class="p">,</span>
 <span class="w">  </span><span class="n">GError</span><span class="o">**</span><span class="w"> </span><span class="n">error</span>
 <span class="p">)</span>
 </pre></div>
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         Description
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         <p>Available since: 1.0.0</p>


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         Parameters
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       <div class="docblock">
         <dl class="arguments">

           <dt class="arg-name"><code>row_group_index</code></dt>
           <dd class="arg-description">
             <p><em>Type:</em>&nbsp;<code>gint</code></p>
             <p><p>A row group index to be&nbsp;read.</p></p>
             <table>


             </table>
           </dd>

           <dt class="arg-name"><code>column_indices</code></dt>
           <dd class="arg-description">
             <p><em>Type:</em>&nbsp;An array of&nbsp;<code>gint</code></p>
             <p><p>Column indices to be read. <code>NULL</code> means that all columns are read.
   If an index is negative, the index is counted backward from the
   end of the columns. <code>-1</code> means the last&nbsp;column.</p></p>
             <table>

             <tr><td>The argument can be <code>NULL</code>.</td></tr>


             <tr><td>The length of the array is specified in the <code>n_column_indices</code> argument.</td></tr>
             <tr><td title="transfer: none">The data is owned by the caller of the function.</td></tr>

             </table>
           </dd>

           <dt class="arg-name"><code>n_column_indices</code></dt>
           <dd class="arg-description">
             <p><em>Type:</em>&nbsp;<code>gsize</code></p>
             <p><p>The number of elements of <code>column_indices</code>.</p></p>
             <table>


             </table>
           </dd>


           <dt class="arg-name"><code>error</code></dt>
           <dd class="arg-description">
             <p><em>Type:</em>&nbsp;<a href="javascript:void(0)" data-namespace="GLib" data-link="struct.Error.html" class="external"><code>GError **</code></a></p>
             <p>The return location for <a href="https://docs.gtk.org/glib/error-reporting.html#rules-for-use-of-gerror">a recoverable error</a>.</p>
             <table>
               <tr><td>The argument can be <code>NULL</code>.</td></tr>
               <tr><td>If the return location is not <code>NULL</code>, then you must initialize it to a <code>NULL</code> <code>GError*</code>.</td></tr>
               <tr><td>The argument will left initialized to <code>NULL</code> by the method if there are no errors.</td></tr>
               <tr><td>In case of error, the argument will be set to a newly allocated <code>GError</code>; the caller will take ownership of the data, and be responsible for freeing it.</td></tr>
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             <p><em>Type:</em>&nbsp;<a href="javascript:void(0)" data-link="class.Table.html" data-namespace="Arrow" class="external"><code>GArrowTable</code></a></p>
             <p><p>A read <code>GArrowTable</code>.</p></p>
           </div>
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             <table>


             <tr><td title="transfer: full">The caller of the method takes ownership of the data, and is responsible for freeing it.</td></tr>
             <tr><td>The return value can be <code>NULL</code>.</td></tr>

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	<a class="method" href="method.ArrowFileReader.get_metadata.html">get_metadata</a>

	<a class="method" href="method.ArrowFileReader.get_n_row_groups.html">get_n_row_groups</a>

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	<a class="method" href="method.ArrowFileReader.get_schema.html">get_schema</a>

	<a class="method" href="method.ArrowFileReader.read_column_data.html">read_column_data</a>

	<a class="method current" href="method.ArrowFileReader.read_row_group.html">read_row_group</a>

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	<h3>Method</h3>
	<h1><a href="index.html">Parquet</a><span class="sep"></span><a href="class.ArrowFileReader.html">ArrowFileReader</a><span class="sep"></span>read_row_group</h1>
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	<section>
	<div class="docblock">
	<p><span class="emblem available">since: 1.0.0</span></p>
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	<div class="declaration toggle-wrapper">
	<h4 style="display:flex;" id="declaration">
	Declaration
	<a class="anchor" href="#declaration"></a>

	<a class="srclink" title="go to source location" href="https://github.com/apache/arrow/blob/main/c_glib/parquet-glib/arrow-file-reader.h#L52">[src]</a>

	</h4>

	<div class="docblock c-decl">
	<pre><code><div class="highlight"><pre><span></span><span class="n">GArrowTable</span><span class="o">*</span>
	<span class="n">gparquet_arrow_file_reader_read_row_group</span><span class="w"> </span><span class="p">(</span>
	<span class="w"> </span><span class="n">GParquetArrowFileReader</span><span class="o">*</span><span class="w"> </span><span class="n">reader</span><span class="p">,</span>
	<span class="w"> </span><span class="n">gint</span><span class="w"> </span><span class="n">row_group_index</span><span class="p">,</span>
	<span class="w"> </span><span class="n">gint</span><span class="o">*</span><span class="w"> </span><span class="n">column_indices</span><span class="p">,</span>
	<span class="w"> </span><span class="n">gsize</span><span class="w"> </span><span class="n">n_column_indices</span><span class="p">,</span>
	<span class="w"> </span><span class="n">GError</span><span class="o">**</span><span class="w"> </span><span class="n">error</span>
	<span class="p">)</span>
	</pre></div>
	</code></pre>
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	<h4 style="display:flex;" id="description">
	Description
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	<div class="docblock">

	<p>Available since: 1.0.0</p>




	</div>


	</div>


	<div class="parameters toggle-wrapper">
	<h4 id="parameters">
	Parameters
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	</h4>

	<div class="docblock">
	<dl class="arguments">

	<dt class="arg-name"><code>row_group_index</code></dt>
	<dd class="arg-description">
	<p><em>Type:</em> <code>gint</code></p>
	<p><p>A row group index to be read.</p></p>
	<table>









	</table>
	</dd>

	<dt class="arg-name"><code>column_indices</code></dt>
	<dd class="arg-description">
	<p><em>Type:</em> An array of <code>gint</code></p>
	<p><p>Column indices to be read. <code>NULL</code> means that all columns are read.
	If an index is negative, the index is counted backward from the
	end of the columns. <code>-1</code> means the last column.</p></p>
	<table>

	<tr><td>The argument can be <code>NULL</code>.</td></tr>




	<tr><td>The length of the array is specified in the <code>n_column_indices</code> argument.</td></tr>
	<tr><td title="transfer: none">The data is owned by the caller of the function.</td></tr>

	</table>
	</dd>

	<dt class="arg-name"><code>n_column_indices</code></dt>
	<dd class="arg-description">
	<p><em>Type:</em> <code>gsize</code></p>
	<p><p>The number of elements of <code>column_indices</code>.</p></p>
	<table>









	</table>
	</dd>



	<dt class="arg-name"><code>error</code></dt>
	<dd class="arg-description">
	<p><em>Type:</em> <a href="javascript:void(0)" data-namespace="GLib" data-link="struct.Error.html" class="external"><code>GError **</code></a></p>
	<p>The return location for <a href="https://docs.gtk.org/glib/error-reporting.html#rules-for-use-of-gerror">a recoverable error</a>.</p>
	<table>
	<tr><td>The argument can be <code>NULL</code>.</td></tr>
	<tr><td>If the return location is not <code>NULL</code>, then you must initialize it to a <code>NULL</code> <code>GError*</code>.</td></tr>
	<tr><td>The argument will left initialized to <code>NULL</code> by the method if there are no errors.</td></tr>
	<tr><td>In case of error, the argument will be set to a newly allocated <code>GError</code>; the caller will take ownership of the data, and be responsible for freeing it.</td></tr>
	</table>
	</dd>

	</dl>
	</div>
	</div>



	<div class="return-value toggle-wrapper">
	<h4 id="return-value">
	Return value
	<a href="#return-value" class="anchor"></a>
	</h4>

	<div class="docblock">
	<div class="returns">
	<div class="arg-description">
	<p><em>Type:</em> <a href="javascript:void(0)" data-link="class.Table.html" data-namespace="Arrow" class="external"><code>GArrowTable</code></a></p>
	<p><p>A read <code>GArrowTable</code>.</p></p>
	</div>
	<div>
	<table>



	<tr><td title="transfer: full">The caller of the method takes ownership of the data, and is responsible for freeing it.</td></tr>
	<tr><td>The return value can be <code>NULL</code>.</td></tr>

	</table>
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