title: How to grep by line/element that contains no characters
body: <p>I have a character vector with a number of elements.</p>
  
  <pre><code>(tmpsp &lt;- c("Hi my name is Gary", "", "Welcome to my house", "", "    Do you like tea?"))
  
  [1] "Hi my name is Gary"
  
  [2] ""
  
  [3] "Welcome to my house"
  
  [4] ""
  
  [5] "    Do you like tea?"
  </code></pre>
  
  <p>Some elements/lines of the vector are simply empty which I wish to remove.</p>
  
  <p>I've attempted finding these lines with the following grep command</p>
  
  <pre><code>grep("^ ", tmpsp)
  </code></pre>
  
  <p>However it doesn't seem to work.</p>
  
  <p>How can I grep elements that contain no characters?</p>
  
  <p>For example, how would I find/remove elements [2] and [4]</p>