title: Replacement of non-ascii character in R function without warning in devtools::check()
body: <p>I've written a function, which extracts coordinate numbers from strings. E.g. "E 10,9598 °" will be 10.9598. </p>
  
  <pre><code>extract_coordinates &lt;- function(x) {
    coord &lt;- gsub(x = x, pattern = "[ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz]", 
      replacement = "")
    coord &lt;- gsub(x = coord, pattern = "°", replacement = "")
    coord &lt;- gsub(x = coord, pattern = "[:space:]", replacement = "")
    coord &lt;- gsub(x = coord, pattern = ",", replacement = ".")
    as.numeric(coord)
  }
  </code></pre>
  
  <p>When I run devtools::check() though this will give me a warning because "°" is a non-ascii character. I tried using the unicode "U+00B0" as a pattern in gsub but that doesn't work. </p>
  
  <p>How do I have to change my code, so there is no warning anymore?</p>