title: How can I take a slice of a frame or vector by date?
body: <p>I have a data frame where the row.names correspond to date values.</p>
  
  <pre><code>$ cat data.csv
  date    actusers    passive
  2010-12-31  162 55
  2011-01-01  291 167
  2011-01-02  270 200
  2011-01-03  341 269
  2011-01-04  412 324
  2011-01-05  409 309
  2011-01-06  481 329
  2011-01-07  511 358
  2011-01-08  364 213
  
  $ r
  &gt; data = read.csv("data.csv", row.names=1, sep='\t')
  &gt; data
             actusers passive
  2010-12-31      162      55
  2011-01-01      291     167
  2011-01-02      270     200
  2011-01-03      341     269
  2011-01-04      412     324
  2011-01-05      409     309
  2011-01-06      481     329
  2011-01-07      511     358
  2011-01-08      364     213
  </code></pre>
  
  <p>How can I make slices of this data frame by specifying date ranges?</p>