github/shiny
1
1
Fork 0
mirror of https://github.com/rstudio/shiny.git synced 2026-04-29 03:00:45 -04:00
Code Issues Packages Projects Releases Wiki Activity
Files
e9afe3df87107395cdb625fd3e01de7d2ea6f944
shiny/reference/validate.html
wch e9afe3df87 Built site for shiny: 1.7.2@7a77b55
2022-07-06 01:13:49 +00:00

177 lines
15 KiB
HTML
Raw Blame History

<!DOCTYPE html>
<!-- Generated by pkgdown: do not edit by hand --><html lang="en"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><meta charset="utf-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Validate input values and other conditions — validate • shiny</title><!-- favicons --><link rel="icon" type="image/png" sizes="16x16" href="../favicon-16x16.png"><link rel="icon" type="image/png" sizes="32x32" href="../favicon-32x32.png"><link rel="apple-touch-icon" type="image/png" sizes="180x180" href="../apple-touch-icon.png"><link rel="apple-touch-icon" type="image/png" sizes="120x120" href="../apple-touch-icon-120x120.png"><link rel="apple-touch-icon" type="image/png" sizes="76x76" href="../apple-touch-icon-76x76.png"><link rel="apple-touch-icon" type="image/png" sizes="60x60" href="../apple-touch-icon-60x60.png"><!-- jquery --><script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.4.1/jquery.min.js" integrity="sha256-CSXorXvZcTkaix6Yvo6HppcZGetbYMGWSFlBw8HfCJo=" crossorigin="anonymous"></script><!-- Bootstrap --><link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.4.1/css/bootstrap.min.css" integrity="sha256-bZLfwXAP04zRMK2BjiO8iu9pf4FbLqX6zitd+tIvLhE=" crossorigin="anonymous"><script src="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.4.1/js/bootstrap.min.js" integrity="sha256-nuL8/2cJ5NDSSwnKD8VqreErSWHtnEP9E7AySL+1ev4=" crossorigin="anonymous"></script><!-- bootstrap-toc --><link rel="stylesheet" href="../bootstrap-toc.css"><script src="../bootstrap-toc.js"></script><!-- Font Awesome icons --><link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.12.1/css/all.min.css" integrity="sha256-mmgLkCYLUQbXn0B1SRqzHar6dCnv9oZFPEC1g1cwlkk=" crossorigin="anonymous"><link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.12.1/css/v4-shims.min.css" integrity="sha256-wZjR52fzng1pJHwx4aV2AO3yyTOXrcDW7jBpJtTwVxw=" crossorigin="anonymous"><!-- clipboard.js --><script src="https://cdnjs.cloudflare.com/ajax/libs/clipboard.js/2.0.6/clipboard.min.js" integrity="sha256-inc5kl9MA1hkeYUt+EC3BhlIgyp/2jDIyBLS6k3UxPI=" crossorigin="anonymous"></script><!-- headroom.js --><script src="https://cdnjs.cloudflare.com/ajax/libs/headroom/0.11.0/headroom.min.js" integrity="sha256-AsUX4SJE1+yuDu5+mAVzJbuYNPHj/WroHuZ8Ir/CkE0=" crossorigin="anonymous"></script><script src="https://cdnjs.cloudflare.com/ajax/libs/headroom/0.11.0/jQuery.headroom.min.js" integrity="sha256-ZX/yNShbjqsohH1k95liqY9Gd8uOiE1S4vZc+9KQ1K4=" crossorigin="anonymous"></script><!-- pkgdown --><link href="../pkgdown.css" rel="stylesheet"><script src="../pkgdown.js"></script><meta property="og:title" content="Validate input values and other conditions — validate"><meta property="og:description" content='validate() provides convenient mechanism for validating that an output
has all the inputs necessary for successful rendering. It takes any number
of (unnamed) arguments, each representing a condition to test. If any
of condition fails (i.e. is not "truthy"), a special type of
error is signaled to stop execution. If this error is not handled by
application-specific code, it is displayed to the user by Shiny.
If you use validate() in a reactive() validation failures will
automatically propagate to outputs that use the reactive.'><meta property="og:image" content="/logo.png"><!-- mathjax --><script src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.5/MathJax.js" integrity="sha256-nvJJv9wWKEm88qvoQl9ekL2J+k/RWIsaSScxxlsrv8k=" crossorigin="anonymous"></script><script src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.5/config/TeX-AMS-MML_HTMLorMML.js" integrity="sha256-84DKXVJXs0/F8OTMzX4UR909+jtl4G7SPypPavF+GfA=" crossorigin="anonymous"></script><!--[if lt IE 9]>
<script src="https://oss.maxcdn.com/html5shiv/3.7.3/html5shiv.min.js"></script>
<script src="https://oss.maxcdn.com/respond/1.4.2/respond.min.js"></script>
<![endif]--></head><body data-spy="scroll" data-target="#toc">
<div class="container template-reference-topic">
<header><div class="navbar navbar-default navbar-fixed-top" role="navigation">
<div class="container">
<div class="navbar-header">
<button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbar" aria-expanded="false">
<span class="sr-only">Toggle navigation</span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<span class="navbar-brand">
<a class="navbar-link" href="../index.html">shiny</a>
<span class="version label label-default" data-toggle="tooltip" data-placement="bottom" title="">1.7.2</span>
</span>
</div>
<div id="navbar" class="navbar-collapse collapse">
<ul class="nav navbar-nav"><li>
<a href="../reference/index.html">Reference</a>
</li>
<li>
<a href="../news/index.html">Changelog</a>
</li>
</ul><ul class="nav navbar-nav navbar-right"><li>
<a href="https://github.com/rstudio/shiny/" class="external-link">
<span class="fab fa-github fa-lg"></span>
</a>
</li>
</ul></div><!--/.nav-collapse -->
</div><!--/.container -->
</div><!--/.navbar -->
</header><div class="row">
<div class="col-md-9 contents">
<div class="page-header">
<h1>Validate input values and other conditions</h1>
<small class="dont-index">Source: <a href="https://github.com/rstudio/shiny/blob/HEAD/R/utils.R" class="external-link"><code>R/utils.R</code></a></small>
<div class="hidden name"><code>validate.Rd</code></div>
</div>
<div class="ref-description">
<p><code>validate()</code> provides convenient mechanism for validating that an output
has all the inputs necessary for successful rendering. It takes any number
of (unnamed) arguments, each representing a condition to test. If any
of condition fails (i.e. is not <a href="isTruthy.html">"truthy"</a>), a special type of
error is signaled to stop execution. If this error is not handled by
application-specific code, it is displayed to the user by Shiny.</p>
<p>If you use <code>validate()</code> in a <code><a href="reactive.html">reactive()</a></code> validation failures will
automatically propagate to outputs that use the reactive.</p>
</div>
<div id="ref-usage">
<div class="sourceCode"><pre class="sourceCode r"><code><span><span class="fu">validate</span><span class="op">(</span><span class="va">...</span>, errorClass <span class="op">=</span> <span class="fu"><a href="https://rdrr.io/r/base/character.html" class="external-link">character</a></span><span class="op">(</span><span class="fl">0</span><span class="op">)</span><span class="op">)</span></span>
<span></span>
<span><span class="fu">need</span><span class="op">(</span><span class="va">expr</span>, message <span class="op">=</span> <span class="fu"><a href="https://rdrr.io/r/base/paste.html" class="external-link">paste</a></span><span class="op">(</span><span class="va">label</span>, <span class="st">"must be provided"</span><span class="op">)</span>, <span class="va">label</span><span class="op">)</span></span></code></pre></div>
</div>
<div id="arguments">
<h2>Arguments</h2>
<dl><dt>...</dt>
<dd><p>A list of tests. Each test should equal <code>NULL</code> for success,
<code>FALSE</code> for silent failure, or a string for failure with an error
message.</p></dd>
<dt>errorClass</dt>
<dd><p>A CSS class to apply. The actual CSS string will have
<code>shiny-output-error-</code> prepended to this value.</p></dd>
<dt>expr</dt>
<dd><p>An expression to test. The condition will pass if the expression
meets the conditions spelled out in Details.</p></dd>
<dt>message</dt>
<dd><p>A message to convey to the user if the validation condition is
not met. If no message is provided, one will be created using <code>label</code>.
To fail with no message, use <code>FALSE</code> for the message.</p></dd>
<dt>label</dt>
<dd><p>A human-readable name for the field that may be missing. This
parameter is not needed if <code>message</code> is provided, but must be provided
otherwise.</p></dd>
</dl></div>
<div id="need-">
<h2><code>need()</code></h2>
<p>An easy way to provide arguments to <code>validate()</code> is to use <code>need()</code>, which
takes an expression and a string. If the expression is not
<a href="isTruthy.html">"truthy"</a> then the string will be used as the error message.</p>
<p>If "truthiness" is flexible for your use case, you'll need to explicitly
generate a logical values. For example, if you want allow <code>NA</code> but not
<code>NULL</code>, you can <code>!is.null(input$foo)</code>.</p>
<p>If you need validation logic that differs significantly from <code>need()</code>, you
can create your own validation test functions. A passing test should return
<code>NULL</code>. A failing test should return either a string providing the error
to display to the user, or if the failure should happen silently, <code>FALSE</code>.</p>
<p>Alternatively you can use <code>validate()</code> within an <code>if</code> statement, which is
particularly useful for more complex conditions:</p>
<p></p><div class="sourceCode"><pre><code><span id="cb1-1"><a href="#cb1-1"></a><span class="cf">if</span> (input<span class="op">$</span>x <span class="op">&lt;</span><span class="st"> </span><span class="dv">0</span> <span class="op">&amp;&amp;</span><span class="st"> </span>input<span class="op">$</span>choice <span class="op">==</span><span class="st"> "positive"</span>) {</span>
<span id="cb1-2"><a href="#cb1-2"></a> <span class="kw">validate</span>(<span class="st">"If choice is positive then x must be greater than 0"</span>)</span>
<span id="cb1-3"><a href="#cb1-3"></a>}</span></code></pre><p></p></div>
</div>
<div id="ref-examples">
<h2>Examples</h2>
<div class="sourceCode"><pre class="sourceCode r"><code><span class="r-in"><span><span class="co">## Only run examples in interactive R sessions</span></span></span>
<span class="r-in"><span><span class="kw">if</span> <span class="op">(</span><span class="fu"><a href="https://rdrr.io/r/base/interactive.html" class="external-link">interactive</a></span><span class="op">(</span><span class="op">)</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/options.html" class="external-link">options</a></span><span class="op">(</span>device.ask.default <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="va">ui</span> <span class="op">&lt;-</span> <span class="fu"><a href="fluidPage.html">fluidPage</a></span><span class="op">(</span></span></span>
<span class="r-in"><span> <span class="fu"><a href="checkboxGroupInput.html">checkboxGroupInput</a></span><span class="op">(</span><span class="st">'in1'</span>, <span class="st">'Check some letters'</span>, choices <span class="op">=</span> <span class="fu"><a href="https://rdrr.io/r/utils/head.html" class="external-link">head</a></span><span class="op">(</span><span class="va">LETTERS</span><span class="op">)</span><span class="op">)</span>,</span></span>
<span class="r-in"><span> <span class="fu"><a href="selectInput.html">selectizeInput</a></span><span class="op">(</span><span class="st">'in2'</span>, <span class="st">'Select a state'</span>, choices <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">""</span>, <span class="va">state.name</span><span class="op">)</span><span class="op">)</span>,</span></span>
<span class="r-in"><span> <span class="fu"><a href="plotOutput.html">plotOutput</a></span><span class="op">(</span><span class="st">'plot'</span><span class="op">)</span></span></span>
<span class="r-in"><span><span class="op">)</span></span></span>
<span class="r-in"><span></span></span>
<span class="r-in"><span><span class="va">server</span> <span class="op">&lt;-</span> <span class="kw">function</span><span class="op">(</span><span class="va">input</span>, <span class="va">output</span><span class="op">)</span> <span class="op">{</span></span></span>
<span class="r-in"><span> <span class="va">output</span><span class="op">$</span><span class="va">plot</span> <span class="op">&lt;-</span> <span class="fu"><a href="renderPlot.html">renderPlot</a></span><span class="op">(</span><span class="op">{</span></span></span>
<span class="r-in"><span> <span class="fu">validate</span><span class="op">(</span></span></span>
<span class="r-in"><span> <span class="fu">need</span><span class="op">(</span><span class="va">input</span><span class="op">$</span><span class="va">in1</span>, <span class="st">'Check at least one letter!'</span><span class="op">)</span>,</span></span>
<span class="r-in"><span> <span class="fu">need</span><span class="op">(</span><span class="va">input</span><span class="op">$</span><span class="va">in2</span> <span class="op">!=</span> <span class="st">''</span>, <span class="st">'Please choose a state.'</span><span class="op">)</span></span></span>
<span class="r-in"><span> <span class="op">)</span></span></span>
<span class="r-in"><span> <span class="fu"><a href="https://rdrr.io/r/graphics/plot.default.html" class="external-link">plot</a></span><span class="op">(</span><span class="fl">1</span><span class="op">:</span><span class="fl">10</span>, main <span class="op">=</span> <span class="fu"><a href="https://rdrr.io/r/base/paste.html" class="external-link">paste</a></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="va">input</span><span class="op">$</span><span class="va">in1</span>, <span class="va">input</span><span class="op">$</span><span class="va">in2</span><span class="op">)</span>, collapse <span class="op">=</span> <span class="st">', '</span><span class="op">)</span><span class="op">)</span></span></span>
<span class="r-in"><span> <span class="op">}</span><span class="op">)</span></span></span>
<span class="r-in"><span><span class="op">}</span></span></span>
<span class="r-in"><span></span></span>
<span class="r-in"><span><span class="fu"><a href="shinyApp.html">shinyApp</a></span><span class="op">(</span><span class="va">ui</span>, <span class="va">server</span><span class="op">)</span></span></span>
<span class="r-in"><span></span></span>
<span class="r-in"><span><span class="op">}</span></span></span>
</code></pre></div>
</div>
</div>
<div class="col-md-3 hidden-xs hidden-sm" id="pkgdown-sidebar">
<nav id="toc" data-toggle="toc" class="sticky-top"><h2 data-toc-skip>Contents</h2>
</nav></div>
</div>
<footer><div class="copyright">
<p></p><p>Developed by Winston Chang, Joe Cheng, JJ Allaire, Carson Sievert, Barret Schloerke, Yihui Xie, Jeff Allen, Jonathan McPherson, Alan Dipert, Barbara Borges.</p>
</div>
<div class="pkgdown">
<p></p><p>Site built with <a href="https://pkgdown.r-lib.org/" class="external-link">pkgdown</a> 2.0.5.</p>
</div>
</footer></div>
</body></html>
Reference in New Issue View Git Blame Copy Permalink