title: passing odata $filter in httr GET request
body: <p>looking to pass $filter criteria using odata in R's httr package, but keep getting an 'Error 400. The request is badly formed'. </p>
  
  <p>I'm able to paste the url/$filter in my browser and obtain results ok, and am also to obtain results in R without the $filter. It's just using the $filter option in R that I'm getting the error:</p>
  
  <pre><code>library(httr)
  url &lt;- "https://api.prosper.com/api/ListingsHistorical?$filter=year(ListingCreationDate) eq 2014"
  response &lt;- GET(url, authenticate('user', 'pass')
  </code></pre>
  
  <p>Above, in R, is what's throwing the 400 response. In browser works fine.</p>