title: Variable as a column name in data frame
body: <p>Is there any way to use string stored in variable as a column name in a new data frame? The expected result should be:</p>
  
  <pre><code>col.name &lt;- 'col1'
  df &lt;- data.frame(col.name=1:4)
  print(df)
  
  # Real output
    col.name
  1        1
  2        2
  3        3
  4        4
  
  # Expected output
    col1
  1    1
  2    2
  3    3
  4    4
  </code></pre>
  
  <p>I'm aware that I can create data frame and then use <em>names()</em> to rename column or use <em>df[, col.name]</em> for existing object, but I'd like to know if there is any other solution which could be used during creating data frame.</p>