title: R: merge.xts common columns
body: <p>After a call to <code>merge.xts</code> my resulting time-series object has 3 columns named A.1, B.1, C.1. The original xts objects both have A, B, C columns set. I am assuming the merge was performed on all the common columns as per documentation.</p>
  
  <p>I checked the column contents A, B, C and A.1, B.1, C.1. A call to <code>my.merged[my.merged$A.1 != my.merged$A, ]</code> returns no rows for all of these columns.</p>
  
  <p>Why the common columns were not collapsed in just one set?</p>