title: How to refactor a vector?
body: <p>I have this vector </p>
  
  <pre><code>v &lt;- c("firstOne","firstTwo","secondOne")
  </code></pre>
  
  <p>I would like to factor the vector assigning <code>c("firstOne","firstTwo)</code> to the same level (i.e., <code>firstOne</code>). I have tried this:</p>
  
  <pre><code>&gt; factor(v, labels = c("firstOne", "firstOne", "secondOne"))
  [1] firstOne  firstOne  secondOne
  Levels: firstOne firstOne secondOne
  </code></pre>
  
  <p>But I get a duplicate factor (and a warning message advising not to use it). Instead, I would like the output to look like:</p>
  
  <pre><code>[1] firstOne  firstOne      secondOne
  Levels: firstOne secondOne
  </code></pre>
  
  <p>Is there any way to get this output without brutally substituting the character strings?</p>