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<title>5 Defining Data Types | Apache Arrow R Cookbook</title>
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<li class="chapter" data-level="1" data-path="index.html"><a href="index.html"><i class="fa fa-check"></i><b>1</b> Preface</a>
<ul>
<li class="chapter" data-level="1.1" data-path="index.html"><a href="index.html#what-is-arrow"><i class="fa fa-check"></i><b>1.1</b> What is Arrow?</a></li>
<li class="chapter" data-level="1.2" data-path="index.html"><a href="index.html#alternative-resources"><i class="fa fa-check"></i><b>1.2</b> Alternative resources</a></li>
</ul></li>
<li class="chapter" data-level="2" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html"><i class="fa fa-check"></i><b>2</b> Reading and Writing Data - Single Files</a>
<ul>
<li class="chapter" data-level="2.1" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#introduction"><i class="fa fa-check"></i><b>2.1</b> Introduction</a></li>
<li class="chapter" data-level="2.2" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#convert-data-from-a-data-frame-to-an-arrow-table"><i class="fa fa-check"></i><b>2.2</b> Convert data from a data frame to an Arrow Table</a>
<ul>
<li class="chapter" data-level="2.2.1" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#solution"><i class="fa fa-check"></i><b>2.2.1</b> Solution</a></li>
</ul></li>
<li class="chapter" data-level="2.3" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#convert-data-from-an-arrow-table-to-a-data-frame"><i class="fa fa-check"></i><b>2.3</b> Convert data from an Arrow Table to a data frame</a>
<ul>
<li class="chapter" data-level="2.3.1" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#solution-1"><i class="fa fa-check"></i><b>2.3.1</b> Solution</a></li>
<li class="chapter" data-level="2.3.2" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#discussion"><i class="fa fa-check"></i><b>2.3.2</b> Discussion</a></li>
</ul></li>
<li class="chapter" data-level="2.4" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#write-a-parquet-file"><i class="fa fa-check"></i><b>2.4</b> Write a Parquet file</a>
<ul>
<li class="chapter" data-level="2.4.1" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#solution-2"><i class="fa fa-check"></i><b>2.4.1</b> Solution</a></li>
</ul></li>
<li class="chapter" data-level="2.5" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#read-a-parquet-file"><i class="fa fa-check"></i><b>2.5</b> Read a Parquet file</a>
<ul>
<li class="chapter" data-level="2.5.1" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#solution-3"><i class="fa fa-check"></i><b>2.5.1</b> Solution</a></li>
<li class="chapter" data-level="2.5.2" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#discussion-1"><i class="fa fa-check"></i><b>2.5.2</b> Discussion</a></li>
</ul></li>
<li class="chapter" data-level="2.6" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#read-a-parquet-file-from-s3"><i class="fa fa-check"></i><b>2.6</b> Read a Parquet file from S3</a>
<ul>
<li class="chapter" data-level="2.6.1" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#solution-4"><i class="fa fa-check"></i><b>2.6.1</b> Solution</a></li>
<li class="chapter" data-level="2.6.2" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#see-also"><i class="fa fa-check"></i><b>2.6.2</b> See also</a></li>
</ul></li>
<li class="chapter" data-level="2.7" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#filter-columns-while-reading-a-parquet-file"><i class="fa fa-check"></i><b>2.7</b> Filter columns while reading a Parquet file</a>
<ul>
<li class="chapter" data-level="2.7.1" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#solution-5"><i class="fa fa-check"></i><b>2.7.1</b> Solution</a></li>
</ul></li>
<li class="chapter" data-level="2.8" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#write-a-feather-v2arrow-ipc-file"><i class="fa fa-check"></i><b>2.8</b> Write a Feather V2/Arrow IPC file</a>
<ul>
<li class="chapter" data-level="2.8.1" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#solution-6"><i class="fa fa-check"></i><b>2.8.1</b> Solution</a></li>
<li class="chapter" data-level="2.8.2" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#discussion-2"><i class="fa fa-check"></i><b>2.8.2</b> Discussion</a></li>
</ul></li>
<li class="chapter" data-level="2.9" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#read-a-featherarrow-ipc-file"><i class="fa fa-check"></i><b>2.9</b> Read a Feather/Arrow IPC file</a>
<ul>
<li class="chapter" data-level="2.9.1" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#solution-7"><i class="fa fa-check"></i><b>2.9.1</b> Solution</a></li>
</ul></li>
<li class="chapter" data-level="2.10" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#write-streaming-arrow-ipc-files"><i class="fa fa-check"></i><b>2.10</b> Write streaming Arrow IPC files</a>
<ul>
<li class="chapter" data-level="2.10.1" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#solution-8"><i class="fa fa-check"></i><b>2.10.1</b> Solution</a></li>
</ul></li>
<li class="chapter" data-level="2.11" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#read-streaming-arrow-ipc-files"><i class="fa fa-check"></i><b>2.11</b> Read streaming Arrow IPC files</a>
<ul>
<li class="chapter" data-level="2.11.1" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#solution-9"><i class="fa fa-check"></i><b>2.11.1</b> Solution</a></li>
</ul></li>
<li class="chapter" data-level="2.12" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#write-a-csv-file"><i class="fa fa-check"></i><b>2.12</b> Write a CSV file</a>
<ul>
<li class="chapter" data-level="2.12.1" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#solution-10"><i class="fa fa-check"></i><b>2.12.1</b> Solution</a></li>
</ul></li>
<li class="chapter" data-level="2.13" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#read-a-csv-file"><i class="fa fa-check"></i><b>2.13</b> Read a CSV file</a>
<ul>
<li class="chapter" data-level="2.13.1" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#solution-11"><i class="fa fa-check"></i><b>2.13.1</b> Solution</a></li>
</ul></li>
<li class="chapter" data-level="2.14" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#read-a-json-file"><i class="fa fa-check"></i><b>2.14</b> Read a JSON file</a>
<ul>
<li class="chapter" data-level="2.14.1" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#solution-12"><i class="fa fa-check"></i><b>2.14.1</b> Solution</a></li>
</ul></li>
<li class="chapter" data-level="2.15" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#write-a-compressed-single-data-file"><i class="fa fa-check"></i><b>2.15</b> Write a compressed single data file</a>
<ul>
<li class="chapter" data-level="2.15.1" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#solution-13"><i class="fa fa-check"></i><b>2.15.1</b> Solution</a></li>
<li class="chapter" data-level="2.15.2" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#see-also-1"><i class="fa fa-check"></i><b>2.15.2</b> See also</a></li>
</ul></li>
<li class="chapter" data-level="2.16" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#read-compressed-data"><i class="fa fa-check"></i><b>2.16</b> Read compressed data</a>
<ul>
<li class="chapter" data-level="2.16.1" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#solution-14"><i class="fa fa-check"></i><b>2.16.1</b> Solution</a></li>
<li class="chapter" data-level="2.16.2" data-path="reading-and-writing-data---single-files.html"><a href="reading-and-writing-data---single-files.html#discussion-3"><i class="fa fa-check"></i><b>2.16.2</b> Discussion</a></li>
</ul></li>
</ul></li>
<li class="chapter" data-level="3" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html"><i class="fa fa-check"></i><b>3</b> Reading and Writing Data - Multiple Files</a>
<ul>
<li class="chapter" data-level="3.1" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#introduction-1"><i class="fa fa-check"></i><b>3.1</b> Introduction</a></li>
<li class="chapter" data-level="3.2" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#write-data-to-disk---parquet"><i class="fa fa-check"></i><b>3.2</b> Write data to disk - Parquet</a>
<ul>
<li class="chapter" data-level="3.2.1" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#solution-15"><i class="fa fa-check"></i><b>3.2.1</b> Solution</a></li>
<li class="chapter" data-level="3.2.2" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#discussion-4"><i class="fa fa-check"></i><b>3.2.2</b> Discussion</a></li>
</ul></li>
<li class="chapter" data-level="3.3" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#write-partitioned-data---parquet"><i class="fa fa-check"></i><b>3.3</b> Write partitioned data - Parquet</a>
<ul>
<li class="chapter" data-level="3.3.1" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#solution-16"><i class="fa fa-check"></i><b>3.3.1</b> Solution</a></li>
<li class="chapter" data-level="3.3.2" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#discussion-5"><i class="fa fa-check"></i><b>3.3.2</b> Discussion</a></li>
</ul></li>
<li class="chapter" data-level="3.4" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#read-partitioned-data"><i class="fa fa-check"></i><b>3.4</b> Read partitioned data</a>
<ul>
<li class="chapter" data-level="3.4.1" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#solution-17"><i class="fa fa-check"></i><b>3.4.1</b> Solution</a></li>
<li class="chapter" data-level="3.4.2" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#discussion-6"><i class="fa fa-check"></i><b>3.4.2</b> Discussion</a></li>
</ul></li>
<li class="chapter" data-level="3.5" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#write-data-to-disk---featherarrow-ipc-format"><i class="fa fa-check"></i><b>3.5</b> Write data to disk - Feather/Arrow IPC format</a>
<ul>
<li class="chapter" data-level="3.5.1" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#solution-18"><i class="fa fa-check"></i><b>3.5.1</b> Solution</a></li>
</ul></li>
<li class="chapter" data-level="3.6" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#read-in-featherarrow-ipc-data-as-an-arrow-dataset"><i class="fa fa-check"></i><b>3.6</b> Read in Feather/Arrow IPC data as an Arrow Dataset</a>
<ul>
<li class="chapter" data-level="3.6.1" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#solution-19"><i class="fa fa-check"></i><b>3.6.1</b> Solution</a></li>
</ul></li>
<li class="chapter" data-level="3.7" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#write-data-to-disk---csv-format"><i class="fa fa-check"></i><b>3.7</b> Write data to disk - CSV format</a>
<ul>
<li class="chapter" data-level="3.7.1" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#solution-20"><i class="fa fa-check"></i><b>3.7.1</b> Solution</a></li>
</ul></li>
<li class="chapter" data-level="3.8" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#read-in-csv-data-as-an-arrow-dataset"><i class="fa fa-check"></i><b>3.8</b> Read in CSV data as an Arrow Dataset</a>
<ul>
<li class="chapter" data-level="3.8.1" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#solution-21"><i class="fa fa-check"></i><b>3.8.1</b> Solution</a></li>
</ul></li>
<li class="chapter" data-level="3.9" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#read-in-a-csv-dataset-no-headers"><i class="fa fa-check"></i><b>3.9</b> Read in a CSV dataset (no headers)</a>
<ul>
<li class="chapter" data-level="3.9.1" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#solution-22"><i class="fa fa-check"></i><b>3.9.1</b> Solution</a></li>
<li class="chapter" data-level="3.9.2" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#discussion-7"><i class="fa fa-check"></i><b>3.9.2</b> Discussion</a></li>
</ul></li>
<li class="chapter" data-level="3.10" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#write-compressed-partitioned-data"><i class="fa fa-check"></i><b>3.10</b> Write compressed partitioned data</a>
<ul>
<li class="chapter" data-level="3.10.1" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#solution-23"><i class="fa fa-check"></i><b>3.10.1</b> Solution</a></li>
<li class="chapter" data-level="3.10.2" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#discussion-8"><i class="fa fa-check"></i><b>3.10.2</b> Discussion</a></li>
</ul></li>
<li class="chapter" data-level="3.11" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#read-compressed-data-1"><i class="fa fa-check"></i><b>3.11</b> Read compressed data</a>
<ul>
<li class="chapter" data-level="3.11.1" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#solution-24"><i class="fa fa-check"></i><b>3.11.1</b> Solution</a></li>
<li class="chapter" data-level="3.11.2" data-path="reading-and-writing-data---multiple-files.html"><a href="reading-and-writing-data---multiple-files.html#discussion-9"><i class="fa fa-check"></i><b>3.11.2</b> Discussion</a></li>
</ul></li>
</ul></li>
<li class="chapter" data-level="4" data-path="creating-arrow-objects.html"><a href="creating-arrow-objects.html"><i class="fa fa-check"></i><b>4</b> Creating Arrow Objects</a>
<ul>
<li class="chapter" data-level="4.1" data-path="creating-arrow-objects.html"><a href="creating-arrow-objects.html#create-an-arrow-array-from-an-r-object"><i class="fa fa-check"></i><b>4.1</b> Create an Arrow Array from an R object</a>
<ul>
<li class="chapter" data-level="4.1.1" data-path="creating-arrow-objects.html"><a href="creating-arrow-objects.html#solution-25"><i class="fa fa-check"></i><b>4.1.1</b> Solution</a></li>
</ul></li>
<li class="chapter" data-level="4.2" data-path="creating-arrow-objects.html"><a href="creating-arrow-objects.html#create-a-arrow-table-from-an-r-object"><i class="fa fa-check"></i><b>4.2</b> Create a Arrow Table from an R object</a>
<ul>
<li class="chapter" data-level="4.2.1" data-path="creating-arrow-objects.html"><a href="creating-arrow-objects.html#solution-26"><i class="fa fa-check"></i><b>4.2.1</b> Solution</a></li>
</ul></li>
<li class="chapter" data-level="4.3" data-path="creating-arrow-objects.html"><a href="creating-arrow-objects.html#view-the-contents-of-an-arrow-table-or-recordbatch"><i class="fa fa-check"></i><b>4.3</b> View the contents of an Arrow Table or RecordBatch</a>
<ul>
<li class="chapter" data-level="4.3.1" data-path="creating-arrow-objects.html"><a href="creating-arrow-objects.html#solution-27"><i class="fa fa-check"></i><b>4.3.1</b> Solution</a></li>
</ul></li>
<li class="chapter" data-level="4.4" data-path="creating-arrow-objects.html"><a href="creating-arrow-objects.html#manually-create-a-recordbatch-from-an-r-object."><i class="fa fa-check"></i><b>4.4</b> Manually create a RecordBatch from an R object.</a>
<ul>
<li class="chapter" data-level="4.4.1" data-path="creating-arrow-objects.html"><a href="creating-arrow-objects.html#solution-28"><i class="fa fa-check"></i><b>4.4.1</b> Solution</a></li>
</ul></li>
</ul></li>
<li class="chapter" data-level="5" data-path="defining-data-types.html"><a href="defining-data-types.html"><i class="fa fa-check"></i><b>5</b> Defining Data Types</a>
<ul>
<li class="chapter" data-level="5.1" data-path="defining-data-types.html"><a href="defining-data-types.html#introduction-2"><i class="fa fa-check"></i><b>5.1</b> Introduction</a></li>
<li class="chapter" data-level="5.2" data-path="defining-data-types.html"><a href="defining-data-types.html#update-data-type-of-an-existing-arrow-array"><i class="fa fa-check"></i><b>5.2</b> Update data type of an existing Arrow Array</a>
<ul>
<li class="chapter" data-level="5.2.1" data-path="defining-data-types.html"><a href="defining-data-types.html#solution-29"><i class="fa fa-check"></i><b>5.2.1</b> Solution</a></li>
<li class="chapter" data-level="5.2.2" data-path="defining-data-types.html"><a href="defining-data-types.html#discussion-10"><i class="fa fa-check"></i><b>5.2.2</b> Discussion</a></li>
</ul></li>
<li class="chapter" data-level="5.3" data-path="defining-data-types.html"><a href="defining-data-types.html#update-data-type-of-a-field-in-an-existing-arrow-table"><i class="fa fa-check"></i><b>5.3</b> Update data type of a field in an existing Arrow Table</a>
<ul>
<li class="chapter" data-level="5.3.1" data-path="defining-data-types.html"><a href="defining-data-types.html#solution-30"><i class="fa fa-check"></i><b>5.3.1</b> Solution</a></li>
<li class="chapter" data-level="5.3.2" data-path="defining-data-types.html"><a href="defining-data-types.html#no-compat-type"><i class="fa fa-check"></i><b>5.3.2</b> Discussion</a></li>
</ul></li>
<li class="chapter" data-level="5.4" data-path="defining-data-types.html"><a href="defining-data-types.html#specify-data-types-when-creating-an-arrow-table-from-an-r-object"><i class="fa fa-check"></i><b>5.4</b> Specify data types when creating an Arrow table from an R object</a>
<ul>
<li class="chapter" data-level="5.4.1" data-path="defining-data-types.html"><a href="defining-data-types.html#solution-31"><i class="fa fa-check"></i><b>5.4.1</b> Solution</a></li>
</ul></li>
<li class="chapter" data-level="5.5" data-path="defining-data-types.html"><a href="defining-data-types.html#specify-data-types-when-reading-in-files"><i class="fa fa-check"></i><b>5.5</b> Specify data types when reading in files</a>
<ul>
<li class="chapter" data-level="5.5.1" data-path="defining-data-types.html"><a href="defining-data-types.html#solution-32"><i class="fa fa-check"></i><b>5.5.1</b> Solution</a></li>
</ul></li>
</ul></li>
<li class="chapter" data-level="6" data-path="manipulating-data---arrays.html"><a href="manipulating-data---arrays.html"><i class="fa fa-check"></i><b>6</b> Manipulating Data - Arrays</a>
<ul>
<li class="chapter" data-level="6.1" data-path="manipulating-data---arrays.html"><a href="manipulating-data---arrays.html#introduction-3"><i class="fa fa-check"></i><b>6.1</b> Introduction</a></li>
<li class="chapter" data-level="6.2" data-path="manipulating-data---arrays.html"><a href="manipulating-data---arrays.html#filter-by-values-matching-a-predicate-or-mask"><i class="fa fa-check"></i><b>6.2</b> Filter by values matching a predicate or mask</a>
<ul>
<li class="chapter" data-level="6.2.1" data-path="manipulating-data---arrays.html"><a href="manipulating-data---arrays.html#solution-33"><i class="fa fa-check"></i><b>6.2.1</b> Solution</a></li>
<li class="chapter" data-level="6.2.2" data-path="manipulating-data---arrays.html"><a href="manipulating-data---arrays.html#discussion-11"><i class="fa fa-check"></i><b>6.2.2</b> Discussion</a></li>
</ul></li>
<li class="chapter" data-level="6.3" data-path="manipulating-data---arrays.html"><a href="manipulating-data---arrays.html#compute-meanminmax-etc-value-of-an-array"><i class="fa fa-check"></i><b>6.3</b> Compute Mean/Min/Max, etc value of an Array</a>
<ul>
<li class="chapter" data-level="6.3.1" data-path="manipulating-data---arrays.html"><a href="manipulating-data---arrays.html#solution-34"><i class="fa fa-check"></i><b>6.3.1</b> Solution</a></li>
<li class="chapter" data-level="6.3.2" data-path="manipulating-data---arrays.html"><a href="manipulating-data---arrays.html#discussion-12"><i class="fa fa-check"></i><b>6.3.2</b> Discussion</a></li>
</ul></li>
<li class="chapter" data-level="6.4" data-path="manipulating-data---arrays.html"><a href="manipulating-data---arrays.html#count-occurrences-of-elements-in-an-array"><i class="fa fa-check"></i><b>6.4</b> Count occurrences of elements in an Array</a>
<ul>
<li class="chapter" data-level="6.4.1" data-path="manipulating-data---arrays.html"><a href="manipulating-data---arrays.html#solution-35"><i class="fa fa-check"></i><b>6.4.1</b> Solution</a></li>
<li class="chapter" data-level="6.4.2" data-path="manipulating-data---arrays.html"><a href="manipulating-data---arrays.html#discussion-13"><i class="fa fa-check"></i><b>6.4.2</b> Discussion</a></li>
</ul></li>
<li class="chapter" data-level="6.5" data-path="manipulating-data---arrays.html"><a href="manipulating-data---arrays.html#apply-arithmetic-functions-to-arrays."><i class="fa fa-check"></i><b>6.5</b> Apply arithmetic functions to Arrays.</a>
<ul>
<li class="chapter" data-level="6.5.1" data-path="manipulating-data---arrays.html"><a href="manipulating-data---arrays.html#solution-36"><i class="fa fa-check"></i><b>6.5.1</b> Solution</a></li>
<li class="chapter" data-level="6.5.2" data-path="manipulating-data---arrays.html"><a href="manipulating-data---arrays.html#discussion-14"><i class="fa fa-check"></i><b>6.5.2</b> Discussion</a></li>
</ul></li>
<li class="chapter" data-level="6.6" data-path="manipulating-data---arrays.html"><a href="manipulating-data---arrays.html#call-arrow-compute-functions-directly-on-arrays"><i class="fa fa-check"></i><b>6.6</b> Call Arrow compute functions directly on Arrays</a>
<ul>
<li class="chapter" data-level="6.6.1" data-path="manipulating-data---arrays.html"><a href="manipulating-data---arrays.html#solution-37"><i class="fa fa-check"></i><b>6.6.1</b> Solution</a></li>
<li class="chapter" data-level="6.6.2" data-path="manipulating-data---arrays.html"><a href="manipulating-data---arrays.html#discussion-15"><i class="fa fa-check"></i><b>6.6.2</b> Discussion</a></li>
<li class="chapter" data-level="6.6.3" data-path="manipulating-data---arrays.html"><a href="manipulating-data---arrays.html#see-also-2"><i class="fa fa-check"></i><b>6.6.3</b> See also</a></li>
</ul></li>
</ul></li>
<li class="chapter" data-level="7" data-path="manipulating-data---tables.html"><a href="manipulating-data---tables.html"><i class="fa fa-check"></i><b>7</b> Manipulating Data - Tables</a>
<ul>
<li class="chapter" data-level="7.1" data-path="manipulating-data---tables.html"><a href="manipulating-data---tables.html#introduction-4"><i class="fa fa-check"></i><b>7.1</b> Introduction</a></li>
<li class="chapter" data-level="7.2" data-path="manipulating-data---tables.html"><a href="manipulating-data---tables.html#use-dplyr-verbs-in-arrow"><i class="fa fa-check"></i><b>7.2</b> Use dplyr verbs in Arrow</a>
<ul>
<li class="chapter" data-level="7.2.1" data-path="manipulating-data---tables.html"><a href="manipulating-data---tables.html#solution-38"><i class="fa fa-check"></i><b>7.2.1</b> Solution</a></li>
<li class="chapter" data-level="7.2.2" data-path="manipulating-data---tables.html"><a href="manipulating-data---tables.html#discussion-16"><i class="fa fa-check"></i><b>7.2.2</b> Discussion</a></li>
<li class="chapter" data-level="7.2.3" data-path="manipulating-data---tables.html"><a href="manipulating-data---tables.html#see-also-3"><i class="fa fa-check"></i><b>7.2.3</b> See also</a></li>
</ul></li>
<li class="chapter" data-level="7.3" data-path="manipulating-data---tables.html"><a href="manipulating-data---tables.html#use-r-functions-in-dplyr-verbs-in-arrow"><i class="fa fa-check"></i><b>7.3</b> Use R functions in dplyr verbs in Arrow</a>
<ul>
<li class="chapter" data-level="7.3.1" data-path="manipulating-data---tables.html"><a href="manipulating-data---tables.html#solution-39"><i class="fa fa-check"></i><b>7.3.1</b> Solution</a></li>
<li class="chapter" data-level="7.3.2" data-path="manipulating-data---tables.html"><a href="manipulating-data---tables.html#discussion-17"><i class="fa fa-check"></i><b>7.3.2</b> Discussion</a></li>
</ul></li>
<li class="chapter" data-level="7.4" data-path="manipulating-data---tables.html"><a href="manipulating-data---tables.html#use-arrow-functions-in-dplyr-verbs-in-arrow"><i class="fa fa-check"></i><b>7.4</b> Use Arrow functions in dplyr verbs in Arrow</a>
<ul>
<li class="chapter" data-level="7.4.1" data-path="manipulating-data---tables.html"><a href="manipulating-data---tables.html#solution-40"><i class="fa fa-check"></i><b>7.4.1</b> Solution</a></li>
<li class="chapter" data-level="7.4.2" data-path="manipulating-data---tables.html"><a href="manipulating-data---tables.html#discussion-18"><i class="fa fa-check"></i><b>7.4.2</b> Discussion</a></li>
</ul></li>
<li class="chapter" data-level="7.5" data-path="manipulating-data---tables.html"><a href="manipulating-data---tables.html#compute-window-aggregates"><i class="fa fa-check"></i><b>7.5</b> Compute Window Aggregates</a>
<ul>
<li class="chapter" data-level="7.5.1" data-path="manipulating-data---tables.html"><a href="manipulating-data---tables.html#solution-41"><i class="fa fa-check"></i><b>7.5.1</b> Solution</a></li>
<li class="chapter" data-level="7.5.2" data-path="manipulating-data---tables.html"><a href="manipulating-data---tables.html#discusson"><i class="fa fa-check"></i><b>7.5.2</b> Discusson</a></li>
</ul></li>
</ul></li>
<li class="chapter" data-level="8" data-path="using-pyarrow-from-r.html"><a href="using-pyarrow-from-r.html"><i class="fa fa-check"></i><b>8</b> Using PyArrow from R</a>
<ul>
<li class="chapter" data-level="8.1" data-path="using-pyarrow-from-r.html"><a href="using-pyarrow-from-r.html#introduction-5"><i class="fa fa-check"></i><b>8.1</b> Introduction</a></li>
<li class="chapter" data-level="8.2" data-path="using-pyarrow-from-r.html"><a href="using-pyarrow-from-r.html#create-an-arrow-object-using-pyarrow-in-r"><i class="fa fa-check"></i><b>8.2</b> Create an Arrow object using PyArrow in R</a>
<ul>
<li class="chapter" data-level="8.2.1" data-path="using-pyarrow-from-r.html"><a href="using-pyarrow-from-r.html#solution-42"><i class="fa fa-check"></i><b>8.2.1</b> Solution</a></li>
</ul></li>
<li class="chapter" data-level="8.3" data-path="using-pyarrow-from-r.html"><a href="using-pyarrow-from-r.html#call-a-pyarrow-function-from-r"><i class="fa fa-check"></i><b>8.3</b> Call a PyArrow function from R</a>
<ul>
<li class="chapter" data-level="8.3.1" data-path="using-pyarrow-from-r.html"><a href="using-pyarrow-from-r.html#solution-43"><i class="fa fa-check"></i><b>8.3.1</b> Solution</a></li>
</ul></li>
</ul></li>
<li class="chapter" data-level="9" data-path="flight.html"><a href="flight.html"><i class="fa fa-check"></i><b>9</b> Flight</a>
<ul>
<li class="chapter" data-level="9.1" data-path="flight.html"><a href="flight.html#introduction-6"><i class="fa fa-check"></i><b>9.1</b> Introduction</a></li>
<li class="chapter" data-level="9.2" data-path="flight.html"><a href="flight.html#connect-to-a-flight-server"><i class="fa fa-check"></i><b>9.2</b> Connect to a Flight server</a>
<ul>
<li class="chapter" data-level="9.2.1" data-path="flight.html"><a href="flight.html#solution-44"><i class="fa fa-check"></i><b>9.2.1</b> Solution</a></li>
<li class="chapter" data-level="9.2.2" data-path="flight.html"><a href="flight.html#see-also-4"><i class="fa fa-check"></i><b>9.2.2</b> See also</a></li>
</ul></li>
<li class="chapter" data-level="9.3" data-path="flight.html"><a href="flight.html#send-data-to-a-flight-server"><i class="fa fa-check"></i><b>9.3</b> Send data to a Flight server</a>
<ul>
<li class="chapter" data-level="9.3.1" data-path="flight.html"><a href="flight.html#solution-45"><i class="fa fa-check"></i><b>9.3.1</b> Solution</a></li>
</ul></li>
<li class="chapter" data-level="9.4" data-path="flight.html"><a href="flight.html#check-what-resources-exist-on-a-flight-server"><i class="fa fa-check"></i><b>9.4</b> Check what resources exist on a Flight server</a>
<ul>
<li class="chapter" data-level="9.4.1" data-path="flight.html"><a href="flight.html#solution-46"><i class="fa fa-check"></i><b>9.4.1</b> Solution</a></li>
</ul></li>
<li class="chapter" data-level="9.5" data-path="flight.html"><a href="flight.html#retrieve-data-from-a-flight-server"><i class="fa fa-check"></i><b>9.5</b> Retrieve data from a Flight server</a>
<ul>
<li class="chapter" data-level="9.5.1" data-path="flight.html"><a href="flight.html#solution-47"><i class="fa fa-check"></i><b>9.5.1</b> Solution</a></li>
</ul></li>
</ul></li>
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<h1>
<i class="fa fa-circle-o-notch fa-spin"></i><a href="./">Apache Arrow R Cookbook</a>
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<section class="normal" id="section-">
<div id="defining-data-types" class="section level1 hasAnchor" number="5">
<h1><span class="header-section-number">5</span> Defining Data Types<a href="defining-data-types.html#defining-data-types" class="anchor-section" aria-label="Anchor link to header"></a></h1>
<div id="introduction-2" class="section level2 hasAnchor" number="5.1">
<h2><span class="header-section-number">5.1</span> Introduction<a href="defining-data-types.html#introduction-2" class="anchor-section" aria-label="Anchor link to header"></a></h2>
<p>As discussed in previous chapters, Arrow automatically infers the most
appropriate data type when reading in data or converting R objects to Arrow
objects. However, you might want to manually tell Arrow which data types to
use, for example, to ensure interoperability with databases and data warehouse
systems. This chapter includes recipes for:</p>
<ul>
<li>changing the data types of existing Arrow objects</li>
<li>defining data types during the process of creating Arrow objects</li>
</ul>
<p>A table showing the default mappings between R and Arrow data types can be found
in <a href="https://arrow.apache.org/docs/r/articles/arrow.html#r-to-arrow">R data type to Arrow data type mappings</a>.</p>
<p>A table containing Arrow data types, and their R equivalents can be found in
<a href="https://arrow.apache.org/docs/r/articles/arrow.html#arrow-to-r">Arrow data type to R data type mapping</a>.</p>
</div>
<div id="update-data-type-of-an-existing-arrow-array" class="section level2 hasAnchor" number="5.2">
<h2><span class="header-section-number">5.2</span> Update data type of an existing Arrow Array<a href="defining-data-types.html#update-data-type-of-an-existing-arrow-array" class="anchor-section" aria-label="Anchor link to header"></a></h2>
<p>You want to change the data type of an existing Arrow Array.</p>
<div id="solution-29" class="section level3 hasAnchor" number="5.2.1">
<h3><span class="header-section-number">5.2.1</span> Solution<a href="defining-data-types.html#solution-29" class="anchor-section" aria-label="Anchor link to header"></a></h3>
<div class="sourceCode" id="cb71"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb71-1"><a href="defining-data-types.html#cb71-1" tabindex="-1"></a><span class="co"># Create an Array to cast</span></span>
<span id="cb71-2"><a href="defining-data-types.html#cb71-2" tabindex="-1"></a>integer_arr <span class="ot">&lt;-</span> Array<span class="sc">$</span><span class="fu">create</span>(<span class="dv">1</span><span class="sc">:</span><span class="dv">5</span>)</span>
<span id="cb71-3"><a href="defining-data-types.html#cb71-3" tabindex="-1"></a></span>
<span id="cb71-4"><a href="defining-data-types.html#cb71-4" tabindex="-1"></a><span class="co"># Cast to an unsigned int8 type</span></span>
<span id="cb71-5"><a href="defining-data-types.html#cb71-5" tabindex="-1"></a>uint_arr <span class="ot">&lt;-</span> integer_arr<span class="sc">$</span><span class="fu">cast</span>(<span class="at">target_type =</span> <span class="fu">uint8</span>())</span>
<span id="cb71-6"><a href="defining-data-types.html#cb71-6" tabindex="-1"></a></span>
<span id="cb71-7"><a href="defining-data-types.html#cb71-7" tabindex="-1"></a>uint_arr</span></code></pre></div>
<pre><code>## Array
## &lt;uint8&gt;
## [
## 1,
## 2,
## 3,
## 4,
## 5
## ]</code></pre>
</div>
<div id="discussion-10" class="section level3 hasAnchor" number="5.2.2">
<h3><span class="header-section-number">5.2.2</span> Discussion<a href="defining-data-types.html#discussion-10" class="anchor-section" aria-label="Anchor link to header"></a></h3>
<p>There are some data types which are not compatible with each other. Errors will
occur if you try to cast between incompatible data types.</p>
<div class="sourceCode" id="cb73"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb73-1"><a href="defining-data-types.html#cb73-1" tabindex="-1"></a>int_arr <span class="ot">&lt;-</span> Array<span class="sc">$</span><span class="fu">create</span>(<span class="dv">1</span><span class="sc">:</span><span class="dv">5</span>)</span>
<span id="cb73-2"><a href="defining-data-types.html#cb73-2" tabindex="-1"></a>int_arr<span class="sc">$</span><span class="fu">cast</span>(<span class="at">target_type =</span> <span class="fu">binary</span>())</span></code></pre></div>
<div class="sourceCode" id="cb74"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb74-1"><a href="defining-data-types.html#cb74-1" tabindex="-1"></a><span class="do">## Error: NotImplemented: Unsupported cast from int32 to binary using function cast_binary</span></span></code></pre></div>
</div>
</div>
<div id="update-data-type-of-a-field-in-an-existing-arrow-table" class="section level2 hasAnchor" number="5.3">
<h2><span class="header-section-number">5.3</span> Update data type of a field in an existing Arrow Table<a href="defining-data-types.html#update-data-type-of-a-field-in-an-existing-arrow-table" class="anchor-section" aria-label="Anchor link to header"></a></h2>
<p>You want to change the type of one or more fields in an existing Arrow Table.</p>
<div id="solution-30" class="section level3 hasAnchor" number="5.3.1">
<h3><span class="header-section-number">5.3.1</span> Solution<a href="defining-data-types.html#solution-30" class="anchor-section" aria-label="Anchor link to header"></a></h3>
<div class="sourceCode" id="cb75"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb75-1"><a href="defining-data-types.html#cb75-1" tabindex="-1"></a><span class="co"># Set up a tibble to use in this example</span></span>
<span id="cb75-2"><a href="defining-data-types.html#cb75-2" tabindex="-1"></a>oscars <span class="ot">&lt;-</span> tibble<span class="sc">::</span><span class="fu">tibble</span>(</span>
<span id="cb75-3"><a href="defining-data-types.html#cb75-3" tabindex="-1"></a> <span class="at">actor =</span> <span class="fu">c</span>(<span class="st">&quot;Katharine Hepburn&quot;</span>, <span class="st">&quot;Meryl Streep&quot;</span>, <span class="st">&quot;Jack Nicholson&quot;</span>),</span>
<span id="cb75-4"><a href="defining-data-types.html#cb75-4" tabindex="-1"></a> <span class="at">num_awards =</span> <span class="fu">c</span>(<span class="dv">4</span>, <span class="dv">3</span>, <span class="dv">3</span>)</span>
<span id="cb75-5"><a href="defining-data-types.html#cb75-5" tabindex="-1"></a>)</span>
<span id="cb75-6"><a href="defining-data-types.html#cb75-6" tabindex="-1"></a></span>
<span id="cb75-7"><a href="defining-data-types.html#cb75-7" tabindex="-1"></a><span class="co"># Convert tibble to an Arrow table</span></span>
<span id="cb75-8"><a href="defining-data-types.html#cb75-8" tabindex="-1"></a>oscars_arrow <span class="ot">&lt;-</span> <span class="fu">arrow_table</span>(oscars)</span>
<span id="cb75-9"><a href="defining-data-types.html#cb75-9" tabindex="-1"></a></span>
<span id="cb75-10"><a href="defining-data-types.html#cb75-10" tabindex="-1"></a><span class="co"># The default mapping from numeric column &quot;num_awards&quot; is to a double</span></span>
<span id="cb75-11"><a href="defining-data-types.html#cb75-11" tabindex="-1"></a>oscars_arrow</span></code></pre></div>
<pre><code>## Table
## 3 rows x 2 columns
## $actor &lt;string&gt;
## $num_awards &lt;double&gt;</code></pre>
<div class="sourceCode" id="cb77"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb77-1"><a href="defining-data-types.html#cb77-1" tabindex="-1"></a><span class="co"># Set up schema with &quot;num_awards&quot; as integer</span></span>
<span id="cb77-2"><a href="defining-data-types.html#cb77-2" tabindex="-1"></a>oscars_schema <span class="ot">&lt;-</span> <span class="fu">schema</span>(<span class="at">actor =</span> <span class="fu">string</span>(), <span class="at">num_awards =</span> <span class="fu">int16</span>())</span>
<span id="cb77-3"><a href="defining-data-types.html#cb77-3" tabindex="-1"></a></span>
<span id="cb77-4"><a href="defining-data-types.html#cb77-4" tabindex="-1"></a><span class="co"># Cast to an int16</span></span>
<span id="cb77-5"><a href="defining-data-types.html#cb77-5" tabindex="-1"></a>oscars_arrow_int <span class="ot">&lt;-</span> oscars_arrow<span class="sc">$</span><span class="fu">cast</span>(<span class="at">target_schema =</span> oscars_schema)</span>
<span id="cb77-6"><a href="defining-data-types.html#cb77-6" tabindex="-1"></a></span>
<span id="cb77-7"><a href="defining-data-types.html#cb77-7" tabindex="-1"></a>oscars_arrow_int</span></code></pre></div>
<pre><code>## Table
## 3 rows x 2 columns
## $actor &lt;string&gt;
## $num_awards &lt;int16&gt;</code></pre>
</div>
<div id="no-compat-type" class="section level3 hasAnchor" number="5.3.2">
<h3><span class="header-section-number">5.3.2</span> Discussion<a href="defining-data-types.html#no-compat-type" class="anchor-section" aria-label="Anchor link to header"></a></h3>
<p>There are some Arrow data types which do not have any R equivalent. Attempting
to cast to these data types or using a schema which contains them will result in
an error.</p>
<div class="sourceCode" id="cb79"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb79-1"><a href="defining-data-types.html#cb79-1" tabindex="-1"></a><span class="co"># Set up a tibble to use in this example</span></span>
<span id="cb79-2"><a href="defining-data-types.html#cb79-2" tabindex="-1"></a>oscars <span class="ot">&lt;-</span> tibble<span class="sc">::</span><span class="fu">tibble</span>(</span>
<span id="cb79-3"><a href="defining-data-types.html#cb79-3" tabindex="-1"></a> <span class="at">actor =</span> <span class="fu">c</span>(<span class="st">&quot;Katharine Hepburn&quot;</span>, <span class="st">&quot;Meryl Streep&quot;</span>, <span class="st">&quot;Jack Nicholson&quot;</span>),</span>
<span id="cb79-4"><a href="defining-data-types.html#cb79-4" tabindex="-1"></a> <span class="at">num_awards =</span> <span class="fu">c</span>(<span class="dv">4</span>, <span class="dv">3</span>, <span class="dv">3</span>)</span>
<span id="cb79-5"><a href="defining-data-types.html#cb79-5" tabindex="-1"></a>)</span>
<span id="cb79-6"><a href="defining-data-types.html#cb79-6" tabindex="-1"></a></span>
<span id="cb79-7"><a href="defining-data-types.html#cb79-7" tabindex="-1"></a><span class="co"># Convert tibble to an Arrow table</span></span>
<span id="cb79-8"><a href="defining-data-types.html#cb79-8" tabindex="-1"></a>oscars_arrow <span class="ot">&lt;-</span> <span class="fu">arrow_table</span>(oscars)</span>
<span id="cb79-9"><a href="defining-data-types.html#cb79-9" tabindex="-1"></a></span>
<span id="cb79-10"><a href="defining-data-types.html#cb79-10" tabindex="-1"></a><span class="co"># Set up schema with &quot;num_awards&quot; as float16 which doesn&#39;t have an R equivalent</span></span>
<span id="cb79-11"><a href="defining-data-types.html#cb79-11" tabindex="-1"></a>oscars_schema_invalid <span class="ot">&lt;-</span> <span class="fu">schema</span>(<span class="at">actor =</span> <span class="fu">string</span>(), <span class="at">num_awards =</span> <span class="fu">float16</span>())</span>
<span id="cb79-12"><a href="defining-data-types.html#cb79-12" tabindex="-1"></a></span>
<span id="cb79-13"><a href="defining-data-types.html#cb79-13" tabindex="-1"></a><span class="co"># The default mapping from numeric column &quot;num_awards&quot; is to a double</span></span>
<span id="cb79-14"><a href="defining-data-types.html#cb79-14" tabindex="-1"></a>oscars_arrow<span class="sc">$</span><span class="fu">cast</span>(<span class="at">target_schema =</span> oscars_schema_invalid)</span></code></pre></div>
<div class="sourceCode" id="cb80"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb80-1"><a href="defining-data-types.html#cb80-1" tabindex="-1"></a><span class="do">## Error: NotImplemented: Unsupported cast from double to halffloat using function cast_half_float</span></span></code></pre></div>
</div>
</div>
<div id="specify-data-types-when-creating-an-arrow-table-from-an-r-object" class="section level2 hasAnchor" number="5.4">
<h2><span class="header-section-number">5.4</span> Specify data types when creating an Arrow table from an R object<a href="defining-data-types.html#specify-data-types-when-creating-an-arrow-table-from-an-r-object" class="anchor-section" aria-label="Anchor link to header"></a></h2>
<p>You want to manually specify Arrow data types when converting an object from a
data frame to an Arrow object.</p>
<div id="solution-31" class="section level3 hasAnchor" number="5.4.1">
<h3><span class="header-section-number">5.4.1</span> Solution<a href="defining-data-types.html#solution-31" class="anchor-section" aria-label="Anchor link to header"></a></h3>
<div class="sourceCode" id="cb81"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb81-1"><a href="defining-data-types.html#cb81-1" tabindex="-1"></a><span class="co"># Set up a tibble to use in this example</span></span>
<span id="cb81-2"><a href="defining-data-types.html#cb81-2" tabindex="-1"></a>oscars <span class="ot">&lt;-</span> tibble<span class="sc">::</span><span class="fu">tibble</span>(</span>
<span id="cb81-3"><a href="defining-data-types.html#cb81-3" tabindex="-1"></a> <span class="at">actor =</span> <span class="fu">c</span>(<span class="st">&quot;Katharine Hepburn&quot;</span>, <span class="st">&quot;Meryl Streep&quot;</span>, <span class="st">&quot;Jack Nicholson&quot;</span>),</span>
<span id="cb81-4"><a href="defining-data-types.html#cb81-4" tabindex="-1"></a> <span class="at">num_awards =</span> <span class="fu">c</span>(<span class="dv">4</span>, <span class="dv">3</span>, <span class="dv">3</span>)</span>
<span id="cb81-5"><a href="defining-data-types.html#cb81-5" tabindex="-1"></a>)</span>
<span id="cb81-6"><a href="defining-data-types.html#cb81-6" tabindex="-1"></a></span>
<span id="cb81-7"><a href="defining-data-types.html#cb81-7" tabindex="-1"></a><span class="co"># Set up schema with &quot;num_awards&quot; as integer</span></span>
<span id="cb81-8"><a href="defining-data-types.html#cb81-8" tabindex="-1"></a>oscars_schema <span class="ot">&lt;-</span> <span class="fu">schema</span>(<span class="at">actor =</span> <span class="fu">string</span>(), <span class="at">num_awards =</span> <span class="fu">int16</span>())</span>
<span id="cb81-9"><a href="defining-data-types.html#cb81-9" tabindex="-1"></a></span>
<span id="cb81-10"><a href="defining-data-types.html#cb81-10" tabindex="-1"></a><span class="co"># create arrow Table containing data and schema</span></span>
<span id="cb81-11"><a href="defining-data-types.html#cb81-11" tabindex="-1"></a>oscars_data_arrow <span class="ot">&lt;-</span> <span class="fu">arrow_table</span>(oscars, <span class="at">schema =</span> oscars_schema)</span>
<span id="cb81-12"><a href="defining-data-types.html#cb81-12" tabindex="-1"></a></span>
<span id="cb81-13"><a href="defining-data-types.html#cb81-13" tabindex="-1"></a>oscars_data_arrow</span></code></pre></div>
<pre><code>## Table
## 3 rows x 2 columns
## $actor &lt;string&gt;
## $num_awards &lt;int16&gt;</code></pre>
</div>
</div>
<div id="specify-data-types-when-reading-in-files" class="section level2 hasAnchor" number="5.5">
<h2><span class="header-section-number">5.5</span> Specify data types when reading in files<a href="defining-data-types.html#specify-data-types-when-reading-in-files" class="anchor-section" aria-label="Anchor link to header"></a></h2>
<p>You want to manually specify Arrow data types when reading in files.</p>
<div id="solution-32" class="section level3 hasAnchor" number="5.5.1">
<h3><span class="header-section-number">5.5.1</span> Solution<a href="defining-data-types.html#solution-32" class="anchor-section" aria-label="Anchor link to header"></a></h3>
<div class="sourceCode" id="cb83"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb83-1"><a href="defining-data-types.html#cb83-1" tabindex="-1"></a><span class="co"># Set up a tibble to use in this example</span></span>
<span id="cb83-2"><a href="defining-data-types.html#cb83-2" tabindex="-1"></a>oscars <span class="ot">&lt;-</span> tibble<span class="sc">::</span><span class="fu">tibble</span>(</span>
<span id="cb83-3"><a href="defining-data-types.html#cb83-3" tabindex="-1"></a> <span class="at">actor =</span> <span class="fu">c</span>(<span class="st">&quot;Katharine Hepburn&quot;</span>, <span class="st">&quot;Meryl Streep&quot;</span>, <span class="st">&quot;Jack Nicholson&quot;</span>),</span>
<span id="cb83-4"><a href="defining-data-types.html#cb83-4" tabindex="-1"></a> <span class="at">num_awards =</span> <span class="fu">c</span>(<span class="dv">4</span>, <span class="dv">3</span>, <span class="dv">3</span>)</span>
<span id="cb83-5"><a href="defining-data-types.html#cb83-5" tabindex="-1"></a>)</span>
<span id="cb83-6"><a href="defining-data-types.html#cb83-6" tabindex="-1"></a></span>
<span id="cb83-7"><a href="defining-data-types.html#cb83-7" tabindex="-1"></a><span class="co"># write dataset to disk</span></span>
<span id="cb83-8"><a href="defining-data-types.html#cb83-8" tabindex="-1"></a><span class="fu">write_dataset</span>(oscars, <span class="at">path =</span> <span class="st">&quot;oscars_data&quot;</span>)</span>
<span id="cb83-9"><a href="defining-data-types.html#cb83-9" tabindex="-1"></a></span>
<span id="cb83-10"><a href="defining-data-types.html#cb83-10" tabindex="-1"></a><span class="co"># Set up schema with &quot;num_awards&quot; as integer</span></span>
<span id="cb83-11"><a href="defining-data-types.html#cb83-11" tabindex="-1"></a>oscars_schema <span class="ot">&lt;-</span> <span class="fu">schema</span>(<span class="at">actor =</span> <span class="fu">string</span>(), <span class="at">num_awards =</span> <span class="fu">int16</span>())</span>
<span id="cb83-12"><a href="defining-data-types.html#cb83-12" tabindex="-1"></a></span>
<span id="cb83-13"><a href="defining-data-types.html#cb83-13" tabindex="-1"></a><span class="co"># read the dataset in, using the schema instead of inferring the type automatically</span></span>
<span id="cb83-14"><a href="defining-data-types.html#cb83-14" tabindex="-1"></a>oscars_dataset_arrow <span class="ot">&lt;-</span> <span class="fu">open_dataset</span>(<span class="st">&quot;oscars_data&quot;</span>, <span class="at">schema =</span> oscars_schema)</span>
<span id="cb83-15"><a href="defining-data-types.html#cb83-15" tabindex="-1"></a></span>
<span id="cb83-16"><a href="defining-data-types.html#cb83-16" tabindex="-1"></a>oscars_dataset_arrow</span></code></pre></div>
<pre><code>## FileSystemDataset with 1 Parquet file
## actor: string
## num_awards: int16</code></pre>
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