EVOLUTION-MANAGER
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><title>R: Split data frame, apply function, and discard results.</title> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <link rel="stylesheet" type="text/css" href="R.css" /> </head><body> <table width="100%" summary="page for d_ply {plyr}"><tr><td>d_ply {plyr}</td><td style="text-align: right;">R Documentation</td></tr></table> <h2>Split data frame, apply function, and discard results.</h2> <h3>Description</h3> <p>For each subset of a data frame, apply function and discard results. To apply a function for each row, use <code><a href="a_ply.html">a_ply</a></code> with <code>.margins</code> set to <code>1</code>. </p> <h3>Usage</h3> <pre> d_ply( .data, .variables, .fun = NULL, ..., .progress = "none", .inform = FALSE, .drop = TRUE, .print = FALSE, .parallel = FALSE, .paropts = NULL ) </pre> <h3>Arguments</h3> <table summary="R argblock"> <tr valign="top"><td><code>.data</code></td> <td> <p>data frame to be processed</p> </td></tr> <tr valign="top"><td><code>.variables</code></td> <td> <p>variables to split data frame by, as <code><a href="as.quoted.html">as.quoted</a></code> variables, a formula or character vector</p> </td></tr> <tr valign="top"><td><code>.fun</code></td> <td> <p>function to apply to each piece</p> </td></tr> <tr valign="top"><td><code>...</code></td> <td> <p>other arguments passed on to <code>.fun</code></p> </td></tr> <tr valign="top"><td><code>.progress</code></td> <td> <p>name of the progress bar to use, see <code><a href="create_progress_bar.html">create_progress_bar</a></code></p> </td></tr> <tr valign="top"><td><code>.inform</code></td> <td> <p>produce informative error messages? This is turned off by default because it substantially slows processing speed, but is very useful for debugging</p> </td></tr> <tr valign="top"><td><code>.drop</code></td> <td> <p>should combinations of variables that do not appear in the input data be preserved (FALSE) or dropped (TRUE, default)</p> </td></tr> <tr valign="top"><td><code>.print</code></td> <td> <p>automatically print each result? (default: <code>FALSE</code>)</p> </td></tr> <tr valign="top"><td><code>.parallel</code></td> <td> <p>if <code>TRUE</code>, apply function in parallel, using parallel backend provided by foreach</p> </td></tr> <tr valign="top"><td><code>.paropts</code></td> <td> <p>a list of additional options passed into the <code><a href="../../foreach/html/foreach.html">foreach</a></code> function when parallel computation is enabled. This is important if (for example) your code relies on external data or packages: use the <code>.export</code> and <code>.packages</code> arguments to supply them so that all cluster nodes have the correct environment set up for computing.</p> </td></tr> </table> <h3>Value</h3> <p>Nothing </p> <h3>Input</h3> <p>This function splits data frames by variables. </p> <h3>Output</h3> <p>All output is discarded. This is useful for functions that you are calling purely for their side effects like displaying plots or saving output. </p> <h3>References</h3> <p>Hadley Wickham (2011). The Split-Apply-Combine Strategy for Data Analysis. Journal of Statistical Software, 40(1), 1-29. <a href="https://www.jstatsoft.org/v40/i01/">https://www.jstatsoft.org/v40/i01/</a>. </p> <h3>See Also</h3> <p>Other data frame input: <code><a href="daply.html">daply</a>()</code>, <code><a href="ddply.html">ddply</a>()</code>, <code><a href="dlply.html">dlply</a>()</code> </p> <p>Other no output: <code><a href="a_ply.html">a_ply</a>()</code>, <code><a href="l_ply.html">l_ply</a>()</code>, <code><a href="m_ply.html">m_ply</a>()</code> </p> <hr /><div style="text-align: center;">[Package <em>plyr</em> version 1.8.7 <a href="00Index.html">Index</a>]</div> </body></html>