title: Error in loadNamespace(name) : there is no package called ‘devtools’
body: <p>Sorry for duplicate post. I saw similar type of problem here <a href="https://stackoverflow.com/questions/20923209/problems-installing-the-devtools-package">Problems installing the devtools package</a> . But I couldn't able to resolve my issue using the solution mentioned here. So created a new thread</p>
  <p>I have installed devtools in my R studio, version 1.2.1335 running on Windows 10,using</p>
  <pre><code>install.packages('devtools')
  </code></pre>
  <p>Then I ran following command</p>
  <pre><code>devtools::install_github(&quot;twitter/AnomalyDetection&quot;)
  </code></pre>
  <p>But I'm getting error message</p>
  <pre><code>Error in loadNamespace(name) : there is no package called ‘devtools’
  </code></pre>
  <p>I tried to install libcurl4-gnutls-dev to resolve the issue, as mentioned in referred stackoverflow post, using following command</p>
  <pre><code>install.packages('libcurl4-gnutls-dev')
  </code></pre>
  <p>But got the error message</p>
  <pre><code>package ‘libcurl4-gnutls-dev’ is not available (for R version 3.5.1)
  </code></pre>
  <p>Also I tried to run following command in my command prompt</p>
  <pre><code>apt-get -y build-dep libcurl4-gnutls-dev
  apt-get -y install libcurl4-gnutls-dev
  </code></pre>
  <p>But got the error message</p>
  <pre><code>'apt-get' is not recognized as internal or external command
  </code></pre>
  <p>Can you suggest me how to solve this issue?</p>