title: Error: could not find function "read_html"
body: <p>I use this code</p>
  
  <pre><code>library(rvest)
  url&lt;-read_html("http://en.wikipedia.org/wiki/Brazil_national_football_team")
  </code></pre>
  
  <p>And I take back this error </p>
  
  <pre><code>Error: could not find function "read_html"
  </code></pre>
  
  <p>Any idea what's going wrong with this?</p>
  
  <p>Also in case of multiple links like this</p>
  
  <pre><code>library(rvest)
  urls&lt;-html("https://en.wikipedia.org/wiki/Financial_crisis",
  "https://en.wikipedia.org/wiki/Inflection",
  "https://en.wikipedia.org/wiki/Financial_crisis_of_2007%E2%80%9308"
  )
  </code></pre>
  
  <p>I receive this:</p>
  
  <pre><code> Error: is.config(config) is not TRUE
  </code></pre>
  
  <p>How can I make it to work? How is it if I have this links into a txt file?</p>