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| |
| <h1>Open a multi-file dataset</h1> |
| <small class="dont-index">Source: <a href="https://github.com/apache/arrow/blob/main/r/R/dataset.R" class="external-link"><code>R/dataset.R</code></a></small> |
| <div class="d-none name"><code>open_dataset.Rd</code></div> |
| </div> |
| |
| <div class="ref-description section level2"> |
| <p>Arrow Datasets allow you to query against data that has been split across |
| multiple files. This sharding of data may indicate partitioning, which |
| can accelerate queries that only touch some partitions (files). Call |
| <code>open_dataset()</code> to point to a directory of data files and return a |
| <code>Dataset</code>, then use <code>dplyr</code> methods to query it.</p> |
| </div> |
| |
| <div class="section level2"> |
| <h2 id="ref-usage">Usage<a class="anchor" aria-label="anchor" href="#ref-usage"></a></h2> |
| <div class="sourceCode"><pre class="sourceCode r"><code><span><span class="fu">open_dataset</span><span class="op">(</span></span> |
| <span> <span class="va">sources</span>,</span> |
| <span> schema <span class="op">=</span> <span class="cn">NULL</span>,</span> |
| <span> partitioning <span class="op">=</span> <span class="fu"><a href="hive_partition.html">hive_partition</a></span><span class="op">(</span><span class="op">)</span>,</span> |
| <span> hive_style <span class="op">=</span> <span class="cn">NA</span>,</span> |
| <span> unify_schemas <span class="op">=</span> <span class="cn">NULL</span>,</span> |
| <span> format <span class="op">=</span> <span class="fu"><a href="https://rdrr.io/r/base/c.html" class="external-link">c</a></span><span class="op">(</span><span class="st">"parquet"</span>, <span class="st">"arrow"</span>, <span class="st">"ipc"</span>, <span class="st">"feather"</span>, <span class="st">"csv"</span>, <span class="st">"tsv"</span>, <span class="st">"text"</span>, <span class="st">"json"</span><span class="op">)</span>,</span> |
| <span> factory_options <span class="op">=</span> <span class="fu"><a href="https://rdrr.io/r/base/list.html" class="external-link">list</a></span><span class="op">(</span><span class="op">)</span>,</span> |
| <span> <span class="va">...</span></span> |
| <span><span class="op">)</span></span></code></pre></div> |
| </div> |
| |
| <div class="section level2"> |
| <h2 id="arguments">Arguments<a class="anchor" aria-label="anchor" href="#arguments"></a></h2> |
| |
| |
| <dl><dt id="arg-sources">sources<a class="anchor" aria-label="anchor" href="#arg-sources"></a></dt> |
| <dd><p>One of:</p><ul><li><p>a string path or URI to a directory containing data files</p></li> |
| <li><p>a <a href="FileSystem.html">FileSystem</a> that references a directory containing data files |
| (such as what is returned by <code><a href="s3_bucket.html">s3_bucket()</a></code>)</p></li> |
| <li><p>a string path or URI to a single file</p></li> |
| <li><p>a character vector of paths or URIs to individual data files</p></li> |
| <li><p>a list of <code>Dataset</code> objects as created by this function</p></li> |
| <li><p>a list of <code>DatasetFactory</code> objects as created by <code><a href="dataset_factory.html">dataset_factory()</a></code>.</p></li> |
| </ul><p>When <code>sources</code> is a vector of file URIs, they must all use the same protocol |
| and point to files located in the same file system and having the same |
| format.</p></dd> |
| |
| |
| <dt id="arg-schema">schema<a class="anchor" aria-label="anchor" href="#arg-schema"></a></dt> |
| <dd><p><a href="Schema-class.html">Schema</a> for the <code>Dataset</code>. If <code>NULL</code> (the default), the schema |
| will be inferred from the data sources.</p></dd> |
| |
| |
| <dt id="arg-partitioning">partitioning<a class="anchor" aria-label="anchor" href="#arg-partitioning"></a></dt> |
| <dd><p>When <code>sources</code> is a directory path/URI, one of:</p><ul><li><p>a <code>Schema</code>, in which case the file paths relative to <code>sources</code> will be |
| parsed, and path segments will be matched with the schema fields.</p></li> |
| <li><p>a character vector that defines the field names corresponding to those |
| path segments (that is, you're providing the names that would correspond |
| to a <code>Schema</code> but the types will be autodetected)</p></li> |
| <li><p>a <code>Partitioning</code> or <code>PartitioningFactory</code>, such as returned |
| by <code><a href="hive_partition.html">hive_partition()</a></code></p></li> |
| <li><p><code>NULL</code> for no partitioning</p></li> |
| </ul><p>The default is to autodetect Hive-style partitions unless |
| <code>hive_style = FALSE</code>. See the "Partitioning" section for details. |
| When <code>sources</code> is not a directory path/URI, <code>partitioning</code> is ignored.</p></dd> |
| |
| |
| <dt id="arg-hive-style">hive_style<a class="anchor" aria-label="anchor" href="#arg-hive-style"></a></dt> |
| <dd><p>Logical: should <code>partitioning</code> be interpreted as |
| Hive-style? Default is <code>NA</code>, which means to inspect the file paths for |
| Hive-style partitioning and behave accordingly.</p></dd> |
| |
| |
| <dt id="arg-unify-schemas">unify_schemas<a class="anchor" aria-label="anchor" href="#arg-unify-schemas"></a></dt> |
| <dd><p>logical: should all data fragments (files, <code>Dataset</code>s) |
| be scanned in order to create a unified schema from them? If <code>FALSE</code>, only |
| the first fragment will be inspected for its schema. Use this fast path |
| when you know and trust that all fragments have an identical schema. |
| The default is <code>FALSE</code> when creating a dataset from a directory path/URI or |
| vector of file paths/URIs (because there may be many files and scanning may |
| be slow) but <code>TRUE</code> when <code>sources</code> is a list of <code>Dataset</code>s (because there |
| should be few <code>Dataset</code>s in the list and their <code>Schema</code>s are already in |
| memory).</p></dd> |
| |
| |
| <dt id="arg-format">format<a class="anchor" aria-label="anchor" href="#arg-format"></a></dt> |
| <dd><p>A <a href="FileFormat.html">FileFormat</a> object, or a string identifier of the format of |
| the files in <code>x</code>. This argument is ignored when <code>sources</code> is a list of <code>Dataset</code> objects. |
| Currently supported values:</p><ul><li><p>"parquet"</p></li> |
| <li><p>"ipc"/"arrow"/"feather", all aliases for each other; for Feather, note that |
| only version 2 files are supported</p></li> |
| <li><p>"csv"/"text", aliases for the same thing (because comma is the default |
| delimiter for text files</p></li> |
| <li><p>"tsv", equivalent to passing <code>format = "text", delimiter = "\t"</code></p></li> |
| <li><p>"json", for JSON format datasets Note: only newline-delimited JSON (aka ND-JSON) datasets |
| are currently supported |
| Default is "parquet", unless a <code>delimiter</code> is also specified, in which case |
| it is assumed to be "text".</p></li> |
| </ul></dd> |
| |
| |
| <dt id="arg-factory-options">factory_options<a class="anchor" aria-label="anchor" href="#arg-factory-options"></a></dt> |
| <dd><p>list of optional FileSystemFactoryOptions:</p><ul><li><p><code>partition_base_dir</code>: string path segment prefix to ignore when |
| discovering partition information with DirectoryPartitioning. Not |
| meaningful (ignored with a warning) for HivePartitioning, nor is it |
| valid when providing a vector of file paths.</p></li> |
| <li><p><code>exclude_invalid_files</code>: logical: should files that are not valid data |
| files be excluded? Default is <code>FALSE</code> because checking all files up |
| front incurs I/O and thus will be slower, especially on remote |
| filesystems. If false and there are invalid files, there will be an |
| error at scan time. This is the only FileSystemFactoryOption that is |
| valid for both when providing a directory path in which to discover |
| files and when providing a vector of file paths.</p></li> |
| <li><p><code>selector_ignore_prefixes</code>: character vector of file prefixes to ignore |
| when discovering files in a directory. If invalid files can be excluded |
| by a common filename prefix this way, you can avoid the I/O cost of |
| <code>exclude_invalid_files</code>. Not valid when providing a vector of file paths |
| (but if you're providing the file list, you can filter invalid files |
| yourself).</p></li> |
| </ul></dd> |
| |
| |
| <dt id="arg--">...<a class="anchor" aria-label="anchor" href="#arg--"></a></dt> |
| <dd><p>additional arguments passed to <code><a href="dataset_factory.html">dataset_factory()</a></code> when <code>sources</code> |
| is a directory path/URI or vector of file paths/URIs, otherwise ignored. |
| These may include <code>format</code> to indicate the file format, or other |
| format-specific options (see <code><a href="read_delim_arrow.html">read_csv_arrow()</a></code>, <code><a href="read_parquet.html">read_parquet()</a></code> and <code><a href="read_feather.html">read_feather()</a></code> on how to specify these).</p></dd> |
| |
| </dl></div> |
| <div class="section level2"> |
| <h2 id="value">Value<a class="anchor" aria-label="anchor" href="#value"></a></h2> |
| <p>A <a href="Dataset.html">Dataset</a> R6 object. Use <code>dplyr</code> methods on it to query the data, |
| or call <code><a href="Scanner.html">$NewScan()</a></code> to construct a query directly.</p> |
| </div> |
| <div class="section level2"> |
| <h2 id="partitioning">Partitioning<a class="anchor" aria-label="anchor" href="#partitioning"></a></h2> |
| |
| |
| |
| <p>Data is often split into multiple files and nested in subdirectories based on the value of one or more |
| columns in the data. It may be a column that is commonly referenced in |
| queries, or it may be time-based, for some examples. Data that is divided |
| this way is "partitioned," and the values for those partitioning columns are |
| encoded into the file path segments. |
| These path segments are effectively virtual columns in the dataset, and |
| because their values are known prior to reading the files themselves, we can |
| greatly speed up filtered queries by skipping some files entirely.</p> |
| <p>Arrow supports reading partition information from file paths in two forms:</p><ul><li><p>"Hive-style", deriving from the Apache Hive project and common to some |
| database systems. Partitions are encoded as "key=value" in path segments, |
| such as <code>"year=2019/month=1/file.parquet"</code>. While they may be awkward as |
| file names, they have the advantage of being self-describing.</p></li> |
| <li><p>"Directory" partitioning, which is Hive without the key names, like |
| <code>"2019/01/file.parquet"</code>. In order to use these, we need know at least |
| what names to give the virtual columns that come from the path segments.</p></li> |
| </ul><p>The default behavior in <code>open_dataset()</code> is to inspect the file paths |
| contained in the provided directory, and if they look like Hive-style, parse |
| them as Hive. If your dataset has Hive-style partitioning in the file paths, |
| you do not need to provide anything in the <code>partitioning</code> argument to |
| <code>open_dataset()</code> to use them. If you do provide a character vector of |
| partition column names, they will be ignored if they match what is detected, |
| and if they don't match, you'll get an error. (If you want to rename |
| partition columns, do that using <code><a href="https://dplyr.tidyverse.org/reference/select.html" class="external-link">select()</a></code> or <code><a href="https://dplyr.tidyverse.org/reference/rename.html" class="external-link">rename()</a></code> after opening the |
| dataset.). If you provide a <code>Schema</code> and the names match what is detected, |
| it will use the types defined by the Schema. In the example file path above, |
| you could provide a Schema to specify that "month" should be <code><a href="data-type.html">int8()</a></code> |
| instead of the <code><a href="data-type.html">int32()</a></code> it will be parsed as by default.</p> |
| <p>If your file paths do not appear to be Hive-style, or if you pass |
| <code>hive_style = FALSE</code>, the <code>partitioning</code> argument will be used to create |
| Directory partitioning. A character vector of names is required to create |
| partitions; you may instead provide a <code>Schema</code> to map those names to desired |
| column types, as described above. If neither are provided, no partitioning |
| information will be taken from the file paths.</p> |
| </div> |
| <div class="section level2"> |
| <h2 id="see-also">See also<a class="anchor" aria-label="anchor" href="#see-also"></a></h2> |
| <div class="dont-index"><p><a href="https://arrow.apache.org/docs/r/articles/dataset.html"> |
| datasets article</a></p></div> |
| </div> |
| |
| <div class="section level2"> |
| <h2 id="ref-examples">Examples<a class="anchor" aria-label="anchor" href="#ref-examples"></a></h2> |
| <div class="sourceCode"><pre class="sourceCode r"><code><span class="r-in"><span><span class="co"># Set up directory for examples</span></span></span> |
| <span class="r-in"><span><span class="va">tf</span> <span class="op"><-</span> <span class="fu"><a href="https://rdrr.io/r/base/tempfile.html" class="external-link">tempfile</a></span><span class="op">(</span><span class="op">)</span></span></span> |
| <span class="r-in"><span><span class="fu"><a href="https://rdrr.io/r/base/files2.html" class="external-link">dir.create</a></span><span class="op">(</span><span class="va">tf</span><span class="op">)</span></span></span> |
| <span class="r-in"><span></span></span> |
| <span class="r-in"><span><span class="fu"><a href="write_dataset.html">write_dataset</a></span><span class="op">(</span><span class="va">mtcars</span>, <span class="va">tf</span>, partitioning <span class="op">=</span> <span class="st">"cyl"</span><span class="op">)</span></span></span> |
| <span class="r-in"><span></span></span> |
| <span class="r-in"><span><span class="co"># You can specify a directory containing the files for your dataset and</span></span></span> |
| <span class="r-in"><span><span class="co"># open_dataset will scan all files in your directory.</span></span></span> |
| <span class="r-in"><span><span class="fu">open_dataset</span><span class="op">(</span><span class="va">tf</span><span class="op">)</span></span></span> |
| <span class="r-out co"><span class="r-pr">#></span> FileSystemDataset with 3 Parquet files</span> |
| <span class="r-out co"><span class="r-pr">#></span> 11 columns</span> |
| <span class="r-out co"><span class="r-pr">#></span> mpg: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> disp: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> hp: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> drat: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> wt: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> qsec: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> vs: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> am: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> gear: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> carb: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> cyl: int32</span> |
| <span class="r-out co"><span class="r-pr">#></span> </span> |
| <span class="r-out co"><span class="r-pr">#></span> See $metadata for additional Schema metadata</span> |
| <span class="r-in"><span></span></span> |
| <span class="r-in"><span><span class="co"># You can also supply a vector of paths</span></span></span> |
| <span class="r-in"><span><span class="fu">open_dataset</span><span class="op">(</span><span class="fu"><a href="https://rdrr.io/r/base/c.html" class="external-link">c</a></span><span class="op">(</span><span class="fu"><a href="https://rdrr.io/r/base/file.path.html" class="external-link">file.path</a></span><span class="op">(</span><span class="va">tf</span>, <span class="st">"cyl=4/part-0.parquet"</span><span class="op">)</span>, <span class="fu"><a href="https://rdrr.io/r/base/file.path.html" class="external-link">file.path</a></span><span class="op">(</span><span class="va">tf</span>, <span class="st">"cyl=8/part-0.parquet"</span><span class="op">)</span><span class="op">)</span><span class="op">)</span></span></span> |
| <span class="r-out co"><span class="r-pr">#></span> FileSystemDataset with 2 Parquet files</span> |
| <span class="r-out co"><span class="r-pr">#></span> 10 columns</span> |
| <span class="r-out co"><span class="r-pr">#></span> mpg: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> disp: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> hp: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> drat: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> wt: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> qsec: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> vs: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> am: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> gear: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> carb: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> </span> |
| <span class="r-out co"><span class="r-pr">#></span> See $metadata for additional Schema metadata</span> |
| <span class="r-in"><span></span></span> |
| <span class="r-in"><span><span class="co">## You must specify the file format if using a format other than parquet.</span></span></span> |
| <span class="r-in"><span><span class="va">tf2</span> <span class="op"><-</span> <span class="fu"><a href="https://rdrr.io/r/base/tempfile.html" class="external-link">tempfile</a></span><span class="op">(</span><span class="op">)</span></span></span> |
| <span class="r-in"><span><span class="fu"><a href="https://rdrr.io/r/base/files2.html" class="external-link">dir.create</a></span><span class="op">(</span><span class="va">tf2</span><span class="op">)</span></span></span> |
| <span class="r-in"><span><span class="fu"><a href="write_dataset.html">write_dataset</a></span><span class="op">(</span><span class="va">mtcars</span>, <span class="va">tf2</span>, format <span class="op">=</span> <span class="st">"ipc"</span><span class="op">)</span></span></span> |
| <span class="r-in"><span><span class="co"># This line will results in errors when you try to work with the data</span></span></span> |
| <span class="r-in"><span><span class="kw">if</span> <span class="op">(</span><span class="cn">FALSE</span><span class="op">)</span> <span class="op">{</span> <span class="co"># \dontrun{</span></span></span> |
| <span class="r-in"><span><span class="fu">open_dataset</span><span class="op">(</span><span class="va">tf2</span><span class="op">)</span></span></span> |
| <span class="r-in"><span><span class="op">}</span> <span class="co"># }</span></span></span> |
| <span class="r-in"><span><span class="co"># This line will work</span></span></span> |
| <span class="r-in"><span><span class="fu">open_dataset</span><span class="op">(</span><span class="va">tf2</span>, format <span class="op">=</span> <span class="st">"ipc"</span><span class="op">)</span></span></span> |
| <span class="r-out co"><span class="r-pr">#></span> FileSystemDataset with 1 Feather file</span> |
| <span class="r-out co"><span class="r-pr">#></span> 11 columns</span> |
| <span class="r-out co"><span class="r-pr">#></span> mpg: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> cyl: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> disp: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> hp: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> drat: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> wt: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> qsec: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> vs: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> am: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> gear: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> carb: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> </span> |
| <span class="r-out co"><span class="r-pr">#></span> See $metadata for additional Schema metadata</span> |
| <span class="r-in"><span></span></span> |
| <span class="r-in"><span><span class="co">## You can specify file partitioning to include it as a field in your dataset</span></span></span> |
| <span class="r-in"><span><span class="co"># Create a temporary directory and write example dataset</span></span></span> |
| <span class="r-in"><span><span class="va">tf3</span> <span class="op"><-</span> <span class="fu"><a href="https://rdrr.io/r/base/tempfile.html" class="external-link">tempfile</a></span><span class="op">(</span><span class="op">)</span></span></span> |
| <span class="r-in"><span><span class="fu"><a href="https://rdrr.io/r/base/files2.html" class="external-link">dir.create</a></span><span class="op">(</span><span class="va">tf3</span><span class="op">)</span></span></span> |
| <span class="r-in"><span><span class="fu"><a href="write_dataset.html">write_dataset</a></span><span class="op">(</span><span class="va">airquality</span>, <span class="va">tf3</span>, partitioning <span class="op">=</span> <span class="fu"><a href="https://rdrr.io/r/base/c.html" class="external-link">c</a></span><span class="op">(</span><span class="st">"Month"</span>, <span class="st">"Day"</span><span class="op">)</span>, hive_style <span class="op">=</span> <span class="cn">FALSE</span><span class="op">)</span></span></span> |
| <span class="r-in"><span></span></span> |
| <span class="r-in"><span><span class="co"># View files - you can see the partitioning means that files have been written</span></span></span> |
| <span class="r-in"><span><span class="co"># to folders based on Month/Day values</span></span></span> |
| <span class="r-in"><span><span class="va">tf3_files</span> <span class="op"><-</span> <span class="fu"><a href="https://rdrr.io/r/base/list.files.html" class="external-link">list.files</a></span><span class="op">(</span><span class="va">tf3</span>, recursive <span class="op">=</span> <span class="cn">TRUE</span><span class="op">)</span></span></span> |
| <span class="r-in"><span></span></span> |
| <span class="r-in"><span><span class="co"># With no partitioning specified, dataset contains all files but doesn't include</span></span></span> |
| <span class="r-in"><span><span class="co"># directory names as field names</span></span></span> |
| <span class="r-in"><span><span class="fu">open_dataset</span><span class="op">(</span><span class="va">tf3</span><span class="op">)</span></span></span> |
| <span class="r-out co"><span class="r-pr">#></span> FileSystemDataset with 153 Parquet files</span> |
| <span class="r-out co"><span class="r-pr">#></span> 4 columns</span> |
| <span class="r-out co"><span class="r-pr">#></span> Ozone: int32</span> |
| <span class="r-out co"><span class="r-pr">#></span> Solar.R: int32</span> |
| <span class="r-out co"><span class="r-pr">#></span> Wind: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> Temp: int32</span> |
| <span class="r-out co"><span class="r-pr">#></span> </span> |
| <span class="r-out co"><span class="r-pr">#></span> See $metadata for additional Schema metadata</span> |
| <span class="r-in"><span></span></span> |
| <span class="r-in"><span><span class="co"># Now that partitioning has been specified, your dataset contains columns for Month and Day</span></span></span> |
| <span class="r-in"><span><span class="fu">open_dataset</span><span class="op">(</span><span class="va">tf3</span>, partitioning <span class="op">=</span> <span class="fu"><a href="https://rdrr.io/r/base/c.html" class="external-link">c</a></span><span class="op">(</span><span class="st">"Month"</span>, <span class="st">"Day"</span><span class="op">)</span><span class="op">)</span></span></span> |
| <span class="r-out co"><span class="r-pr">#></span> FileSystemDataset with 153 Parquet files</span> |
| <span class="r-out co"><span class="r-pr">#></span> 6 columns</span> |
| <span class="r-out co"><span class="r-pr">#></span> Ozone: int32</span> |
| <span class="r-out co"><span class="r-pr">#></span> Solar.R: int32</span> |
| <span class="r-out co"><span class="r-pr">#></span> Wind: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> Temp: int32</span> |
| <span class="r-out co"><span class="r-pr">#></span> Month: int32</span> |
| <span class="r-out co"><span class="r-pr">#></span> Day: int32</span> |
| <span class="r-out co"><span class="r-pr">#></span> </span> |
| <span class="r-out co"><span class="r-pr">#></span> See $metadata for additional Schema metadata</span> |
| <span class="r-in"><span></span></span> |
| <span class="r-in"><span><span class="co"># If you want to specify the data types for your fields, you can pass in a Schema</span></span></span> |
| <span class="r-in"><span><span class="fu">open_dataset</span><span class="op">(</span><span class="va">tf3</span>, partitioning <span class="op">=</span> <span class="fu"><a href="schema.html">schema</a></span><span class="op">(</span>Month <span class="op">=</span> <span class="fu"><a href="data-type.html">int8</a></span><span class="op">(</span><span class="op">)</span>, Day <span class="op">=</span> <span class="fu"><a href="data-type.html">int8</a></span><span class="op">(</span><span class="op">)</span><span class="op">)</span><span class="op">)</span></span></span> |
| <span class="r-out co"><span class="r-pr">#></span> FileSystemDataset with 153 Parquet files</span> |
| <span class="r-out co"><span class="r-pr">#></span> 6 columns</span> |
| <span class="r-out co"><span class="r-pr">#></span> Ozone: int32</span> |
| <span class="r-out co"><span class="r-pr">#></span> Solar.R: int32</span> |
| <span class="r-out co"><span class="r-pr">#></span> Wind: double</span> |
| <span class="r-out co"><span class="r-pr">#></span> Temp: int32</span> |
| <span class="r-out co"><span class="r-pr">#></span> Month: int8</span> |
| <span class="r-out co"><span class="r-pr">#></span> Day: int8</span> |
| <span class="r-out co"><span class="r-pr">#></span> </span> |
| <span class="r-out co"><span class="r-pr">#></span> See $metadata for additional Schema metadata</span> |
| </code></pre></div> |
| </div> |
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