title: filter data.table rows using two numerical columns
body: <p>Trying to discard rows where V1 is greater than 1 OR V3 is greater than 0.5</p>
  
  <pre><code>library(data.table)
  set.seed(45L)
  DT &lt;- data.table(V1=c(1L,2L),
                   V2=LETTERS[1:3],
                   V3=round(rnorm(4),4),
                   V4=1:12)
  
  # tried this approach to get the rows 
  DT[ .(V1&lt;1,V3&lt;0.5) ]
  
  Error in bmerge(i, x, leftcols, rightcols, io, xo, roll, rollends, nomatch,  : 
    x.'V2' is a character column being joined to i.'V2' which is type logical'.
  
  # found this solution, but it's a very dirty one. Looking for cleaner approach.
  # and being afraid of duplicate rows that meet the two conditions
  
  rbind(DT[ V1&lt;1 ],DT[ V3&lt;0.5 ])
  </code></pre>