title: Get list of available data frames
body: <p>How do I get vector of data frame names available in current environment? I've tried:</p>
  
  <pre><code>sapply(ls(), is.data.frame)
  </code></pre>
  
  <p>But this fails because <code>ls</code> returns vector of strings. I'm planning to use this list as a input for dynamic selection in Shiny app.</p>