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(This article was first published on <strong><a href="http://www.win-vector.com/blog/2018/03/r-tip-get-out-of-the-habit-of-calling-view-directly/"> R – Win-Vector Blog</a></strong>, and kindly contributed to <a rel="nofollow" href="https://www.r-bloggers.com/">R-bloggers)</a> </div>
<p><a rel="nofollow" href="https://www.r-project.org/" target="_blank">R</a> <a rel="nofollow" href="http://www.win-vector.com/blog/tag/r-tips/" target="_blank">tip</a>: get out of the habit of calling <code>View()</code> directly.</p>
<p><code>View()</code> only works correctly in interactive environments, not currently in <a rel="nofollow" href="https://rmarkdown.rstudio.com/" target="_blank">RMarkdown</a> contexts. It is better to call something else that safely dispatches to <code>View()</code>, or to something else depending if you are in an interactive or non-interactive session.</p>
<p>The following code will work interactively, in <code>RMarkdown</code>, or even in a <code>reprex</code>.</p>
<pre>
#' Invoke a spreadsheet like viewer when appropriate.
#' 
#' @param x R object to view
#' @param title title for viewer
#' @param n number of rows to show
#' @return invoke view or format object
#' 
view &lt;- function(
  x, 
  ...,
  title = as.character(substitute(x)), 
  n = 200) {
  UseMethod(&quot;view&quot;, x)
}
view.data.frame &lt;- function(
  x, 
  ...,
  title = as.character(substitute(x)), 
  n = 200) {
  wrapr::stop_if_dot_args(substitute(list(...)), 
                          &quot;view&quot;)
  if(interactive()) {
    View(x, title = title)
  } else {
    if(require(&quot;knitr&quot;, 
               character.only = TRUE, 
               quietly = TRUE)) {
      knitr::kable(head(x, n = n), 
                   caption = title)
    } else {
      print(format(head(x, n = n)))
    }
  }
}

view(mtcars)
</pre>
<p>The above code is a nice safe way to view frames which falls back to a <a rel="nofollow" href="http://dirk.eddelbuettel.com/blog/2018/02/28/#017_dependencies" target="_blank">low dependency</a> solution when needed.</p>
<p>For more on <code>wrapr::stop_if_dot_args()</code> please see <a rel="nofollow" href="http://www.win-vector.com/blog/2018/02/r-tip-force-named-arguments/" target="_blank">R Tip: Force Named Arguments</a>.</p>
	<p>
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