title: R: string var like list menber name
body: <p>in R list, I can set the list member name with </p>
  
  <pre><code>&gt; l = list()
  &gt; l$a = 1:10
  &gt; l
  $a
   [1]  1  2  3  4  5  6  7  8  9 10
  </code></pre>
  
  <p>but, How I can set the list member name from a string varible ? like</p>
  
  <pre><code>&gt; var_name = "a"
  &gt; l = list()
  &gt; l$var_name &lt;- 1:10
  &gt; l
  $var_name
   [1]  1  2  3  4  5  6  7  8  9 10
  </code></pre>