title: replace string in dataframe
body: <p>I'm trying to replace a certain string in a large data.frame. I just found the following solution but <code>gsub</code> doesn't preserve the original data.frame layout. How can I achieve this. </p>
  
  <p>I mean I want to replace a string and don't want to change the layout of the df.</p>
  
  <p>Consider this example:</p>
  
  <pre><code>test&lt;-data.frame(a=c("a","b","c","d"),b=c("a","e","g","h"),c=c("i","j","k","a"))
  gsub("a","new",test)
  </code></pre>
  
  <p>Thx</p>