title: Make sequential numeric column names prefixed with a letter
body: <p>I want to add a label to my dataset. However, the problems is that there are so many columns in my data sets so adding the labels manually is laborious.</p>
  
  <p>I have 33 columns including the <code>label</code> column at the end as below.</p>
  
  <pre><code>features &lt;- c("f1","f2","f3","f4","f5","f6","f7","f8","f9","f10",
                "f11","f12","f13","f14","f15","f16","f17","f18","f19","f20",
                "f21","f22","f23","f24","f25","f26","f27","f28","f29","f30",
                "f31","f32","label")
  colnames(urc_training_norm) &lt;- features
  </code></pre>
  
  <p>As you can see, typing manually the each column is annoying to add the column names that I wanted.</p>
  
  <p>Is there any better way to generate these names?</p>