title: How to concatenate, element-wise, two document corpora in R using tm
body: <p>Start with two corpora of documents, each with the same number of documents:</p>
  
  <pre><code>library(tm)
  c1 &lt;- Corpus(VectorSource(c("document 1 corpus 1 text", "document 2 corpus 1 text")))
  c2 &lt;- Corpus(VectorSource(c("document 1 corpus 2 text", "document 2 corpus 2 text")))
  </code></pre>
  
  <p>I want a single corpus of the same number of documents with the terms combined element-wise to form a single document, the equivalent of: </p>
  
  <pre><code>c3 &lt;- Corpus(VectorSource(c("document 1 corpus 1 text document 1 corpus 2 text", 
                              "document 2 corpus 1 text document 2 corpus 2 text"))
  </code></pre>
  
  <p>Searching has turned up the <code>tm_combine</code> function, but that combines the documents from different corpora into a single corpus with twice the (or, the sum of the individual) number of documents. </p>