title: How to get value by column name in R?
body: <p>I have one tab delimited file.</p>
  
  <p>cat file</p>
  
  <pre><code>A      B     C
  2      3     4 
  3      4     5
  2      6     6
  </code></pre>
  
  <p>infile&lt;-read.table("file",header=TRUE)</p>
  
  <p>I need to get value for column which has header = "A".</p>
  
  <pre><code> A 
   2
   3
   2
  </code></pre>
  
  <p>How can i get it? </p>