title: "Aggregating" non-numeric variables in Reshape
body: <p>I have a dataset in long format and would like to convert it into a wide format using Reshape or any pre-processing prior to Reshape. The difficulty is that "value" variable is non-numeric. Note there is a legit duplicate record in the original data as well. The following code shows data layout for each. </p>
  
  <pre><code>id = c(1, 1, 1, 1, 1, 1, 1)
  month &lt;- c("jan", "feb", "feb", "march", "april", "april", "april")
  stress &lt;- c("mild", "mild", "high", "moderate", "mild", "high", "mild")
  Longdata &lt;- data.frame(id, month, stress, stringsAsFactors = FALSE)
  </code></pre>
  
  <p>This is the orginal format:</p>
  
  <pre><code>&gt; Longdata
    id month   stress
  1  1   jan     mild
  2  1   feb     mild
  3  1   feb     high
  4  1 march moderate
  5  1 april     mild
  6  1 april     high
  7  1 april     mild
  </code></pre>
  
  <p>This is how I would like to get data organized:</p>
  
  <pre><code>id &lt;- c(1)
  jan &lt;- c("mild")
  feb &lt;- c("mild-high")
  march &lt;- c("moderate")
  april &lt;- c("mild-high-mild")
  widedata &lt;- data.frame(id, jan, feb, march, april, stringsAsFactors = FALSE)
  &gt; widedata
    id  jan       feb    march          april
  1  1 mild mild-high moderate mild-high-mild
  </code></pre>