title: How do I create component (subset) dataframes in R based on column values?
body: <p>I'd like to split a dataframe into several component dataframes based on the values in one column.
  In my example, I want to split dat into dat.1, dat.2 and dat.3 using the values in column "cond".
  Is there a simple command which could achieve this?</p>
  
  <pre><code>dat
  sub cond    trial   time01  time02
  1   1   1   2774    8845
  1   1   2   2697    9945
  1   2   1   2219    9291
  1   2   2   3886    7890
  1   3   1   4011    9032
  2   2   1   3478    8827
  2   2   2   2263    8321
  2   3   1   4312    7576
  3   1   1   4219    7891
  3   3   1   3992    6674
  
  
  dat.1               
  sub cond    trial   time01  time02
  1   1   1   2774    8845
  1   1   2   2697    9945
  3   1   1   4219    7891    
  
  dat.2               
  sub cond    trial   time01  time02
  2   2   1   3478    8827
  2   2   2   2263    8321
  1   2   1   2219    9291
  1   2   2   3886    7890
  
  dat.3               
  sub cond    trial   time01  time02
  1   3   1   4011    9032
  2   3   1   4312    7576
  3   3   1   3992    6674
  </code></pre>
  
  <p>Perhaps because I'm an R novice I've still not determined how to do this despite browsing and trying the solutions proposed in several similar forum queries. Thank you in advance for any replies.</p>
  
  <p>A <code>dput()</code> of the data is:</p>
  
  <pre><code>structure(list(sub = c(1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 3L, 3L
  ), cond = c(1L, 1L, 2L, 2L, 3L, 2L, 2L, 3L, 1L, 3L), trial = c(1L, 
  2L, 1L, 2L, 1L, 1L, 2L, 1L, 1L, 1L), time01 = c(2774L, 2697L, 
  2219L, 3886L, 4011L, 3478L, 2263L, 4312L, 4219L, 3992L), time02 = c(8845L, 
  9945L, 9291L, 7890L, 9032L, 8827L, 8321L, 7576L, 7891L, 6674L
  )), .Names = c("sub", "cond", "trial", "time01", "time02"), class = "data.frame", row.names = c(NA, 
  -10L))
  </code></pre>