title: How to read a large dbf file in chunks with R
body: <p>I have a 23G DBF file. Let's say it has 3 columns: x y z and 1000 rows (for illustration purpose). I only need the rows that have y from the followings c("good,"excellent","perfect"). And save the rows as a .csv file. </p>
  
  <p>Actually, I don't know what y is really called in the big file, maybe 'yy' or 'Idontknow'. So the first thing is to check the headers so I know what column I should use for filtering.</p>
  
  <p>I know there may first construct a connection and then read in data in chunks using functions such as read.table() and read.fwf(). However, this idea does not seem to work for DBF files.</p>
  
  <p>Any tips?</p>
  
  <p>Thank you.</p>