title: How can I encode an R vector of length 1 as a single value in json using the jsonlite R package?
body: <p>I am trying to encode R lists into json using the jsonlite package and the toJSON function. I have a simple item like:</p>
  
  <pre><code>list(op='abc')
  </code></pre>
  
  <p>I'd like that to become:</p>
  
  <pre><code>{
    "op" : "abc"
  }
  </code></pre>
  
  <p>Instead, I get:</p>
  
  <pre><code>{
    "op" : ["abc"]
  }
  </code></pre>
  
  <p>The API to which I am trying to feed this json chokes on the latter and requires the former.  Any suggestions on how to get the former behavior from jsonlite (or another R json package)?</p>