title: FREAD row criteria in R
body: <p>Since I have more than 10gb of data, I am looking to find a way to create a row filter criteria before reading the dataset into R so that the data read would be less than 10gb and the time required would be less. 
  Currently I am using the fread and even though it has the select criteria c("a","b"), I was not able to find a row filter critera (e.g. Col A > 2).</p>
  
  <p>Is there a workaround for this in fread?
  If not then is there any other way?</p>