title: Naming input and output variables after a column for each column in a a dataframe
body: <p>I have a data frame that is the result of some reshaping with dcast.</p>
  
  <p>I'd like to be able to create a named character variable from each column name except 'id'.</p>
  
  <p>Data:</p>
  
  <pre><code>id &lt;- c("123", "345", "789", "234")
  c10010 &lt;- c(NA, NA, "789", NA)
  c11211 &lt;- c("123", NA, NA, "234")
  c10013 &lt;- c(NA, "345", NA, NA)
  df &lt;- data.frame(id, c10010, c11211, c10013)
  </code></pre>
  
  <p>A non programmatic example of what I'd like to achieve is:</p>
  
  <pre><code>c11211_char &lt;- paste(paste(na.omit(df$c11211)), collapse=",")
  </code></pre>
  
  <p>with the correct output of <code>123,234</code>.</p>
  
  <p>How can I get each column name to replace the <code>c11211</code> instances in the above?</p>