title: using R.zoo to plot multiple series with error bars
body: <p>I have data that looks like this: </p>
  
  <pre><code>   &gt; head(data)
               groupname ob_time dist.mean  dist.sd dur.mean   dur.sd   ct.mean    ct.sd
        1      rowA     0.3  61.67500 39.76515 43.67500 26.35027  8.666667 11.29226
        2      rowA    60.0  45.49167 38.30301 37.58333 27.98207  8.750000 12.46176
        3      rowA   120.0  50.22500 35.89708 40.40000 24.93399  8.000000 10.23363
        4      rowA   180.0  54.05000 41.43919 37.98333 28.03562  8.750000 11.97061
        5      rowA   240.0  51.97500 41.75498 35.60000 25.68243 28.583333 46.14692
        6      rowA   300.0  45.50833 43.10160 32.20833 27.37990 12.833333 14.21800
  </code></pre>
  
  <p>Each groupname is a data series.  Since I want to plot each series separately, I've separated them like this:</p>
  
  <pre><code>&gt; A &lt;- zoo(data[which(groupname=='rowA'),3:8],data[which(groupname=='rowA'),2])
  &gt; B &lt;- zoo(data[which(groupname=='rowB'),3:8],data[which(groupname=='rowB'),2])
  &gt; C &lt;- zoo(data[which(groupname=='rowC'),3:8],data[which(groupname=='rowC'),2])
  </code></pre>
  
  <p>ETA: </p>
  
  <pre><code>Thanks to gd047: Now I'm using this:
  
      z &lt;- dlply(data,.(groupname),function(x) zoo(x[,3:8],x[,2]))
  </code></pre>
  
  <p>The resulting zoo objects look like this:</p>
  
  <pre><code>&gt; head(z$rowA)
            dist.mean  dist.sd dur.mean   dur.sd   ct.mean    ct.sd
       0.3  61.67500 39.76515 43.67500 26.35027  8.666667 11.29226
       60   45.49167 38.30301 37.58333 27.98207  8.750000 12.46176
       120  50.22500 35.89708 40.40000 24.93399  8.000000 10.23363
       180  54.05000 41.43919 37.98333 28.03562  8.750000 11.97061
       240  51.97500 41.75498 35.60000 25.68243 28.583333 46.14692
       300  45.50833 43.10160 32.20833 27.37990 12.833333 14.21800
  </code></pre>
  
  <p>So if I want to plot dist.mean against time and include error bars equal to +/- dist.sd for each series:</p>
  
  <ul>
  <li>how do I combine A,B,C dist.mean and dist.sd?</li>
  <li>how do I make a bar plot, <em>or perhaps better</em>, a line graph of the resulting object?</li>
  </ul>