title: Changing specific element in various variables
body: <p>I've got variables in a dataset like this:</p>
  <pre><code>
  dat1 &lt;- read.table(header=TRUE, text=&quot;
  comp_T1_01 comp_T1_02 comp_T1_03 res_T1_01 res_T1_02 res_T1_03 res_T1_04 
  1 1 2 1 5 5 5
  2 1 3 3 4 4 1
  3 1 3 1 3 2 2
  4 2 5 5 3 2 2
  5 1 4 1 2 1 3
  &quot;)
  
  </code></pre>
  <p>I would like erase the &quot;T1&quot; of all the variables at once. As I have over 100 Variables the &quot;colnames&quot; would be a bit too complicated.<br />
  Is there a command that can do that?</p>
  <p>Thank you!</p>