title: Could not find function "year" after installation from zip file R
body: <p>I'm using R and working on a server without internet connection. So I had to search how to install packages from a zip file. I wanted to use the lubridate package.</p>
  
  <pre><code>install.packages("V:/R/lubridate_1.3.3.zip", repos=NULL)
  </code></pre>
  
  <p>Then I tried to use </p>
  
  <pre><code>library(lubridate) 
  year(data$date)
  </code></pre>
  
  <p>but I received an error that <code>package or namespace load failed for "lubridate"</code>. And the <code>function year could not be found</code>.</p>
  
  <p>Did I forgot any step?</p>