title: subsetting in xts using a parameter holding dates
body: <p>I am familiar with the xts subsetting abilities. However, I can't find an elegant way to subset a <strong>parameterized</strong> range of dates. something like this:</p>
  
  <pre><code>times = c(as.POSIXct("2012-11-03 09:45:00 IST"),
            as.POSIXct("2012-11-05 09:45:00 IST"))
  
  #create an xts object:
  xts.obj = xts(c(1,2),order.by = times)
  
  #filter with these dates:
  start.date = as.POSIXct("2012-11-03")
  end.date = as.POSIXct("2012-11-04")
  
  #instead of xts["2012-11-03"/"2012-11-04"], do something like this:
  xts[start.date:end.date]
  </code></pre>
  
  <p>Does anybody have any idea? Thanks!</p>