[R] allocating factor levels

[Darcy Webber]

Dear R users,

I am working on allocating the rows within a dataframe into some
factor levels.Consider the following dataframe:

               Start.action                  Start.time
1            Start.setting    2010-12-30 17:58:00
2            Start.setting    2010-12-30 18:40:00
3            Start.setting    2010-12-31 22:39:00
4            Start.setting    2010-12-31 23:24:00
5            Start.setting    2011-01-01 00:30:00
6            Start.setting    2011-01-01 01:10:00
7            Start.hauling    2011-01-01 07:07:00
8            Start.hauling    2011-01-01 14:25:00
9            Start.hauling    2011-01-01 21:28:00
10          Start.hauling    2011-01-02 03:38:00
11          Start.hauling    2011-01-02 09:28:00
12          Start.hauling    2011-01-02 14:22:00
13          Start.setting    2011-01-02 20:51:00
14          Start.setting    2011-01-02 21:33:00
15          Start.setting    2011-01-02 22:47:00
16          Start.setting    2011-01-02 23:27:00
17          Start.setting    2011-01-03 00:35:00
18          Start.setting    2011-01-03 01:16:00
19          Start.hauling    2011-01-03 04:31:00
20          Start.hauling    2011-01-03 08:57:00

I am trying to assign a factor level like the one below (named
"action") according to the sequence of setting and hauling occuring in
the "Start.action" column. In fact, it wouldnt even need to be a
factor or character, it could simply be numbered (i.e., the set/haul
prefix is useless as I could simply split it afterwards).

              Start.action                   Start.time   action
1            Start.setting    2010-12-30 17:58:00    set1
2            Start.setting    2010-12-30 18:40:00    set1
3            Start.setting    2010-12-31 22:39:00    set1
4            Start.setting    2010-12-31 23:24:00    set1
5            Start.setting    2011-01-01 00:30:00    set1
6            Start.setting    2011-01-01 01:10:00    set1
7            Start.hauling    2011-01-01 07:07:00   haul1
8            Start.hauling    2011-01-01 14:25:00   haul1
9            Start.hauling    2011-01-01 21:28:00   haul1
10          Start.hauling    2011-01-02 03:38:00   haul1
11          Start.hauling    2011-01-02 09:28:00   haul1
12          Start.hauling    2011-01-02 14:22:00   haul1
13          Start.setting    2011-01-02 20:51:00    set2
14          Start.setting    2011-01-02 21:33:00    set2
15          Start.setting    2011-01-02 22:47:00    set2
16          Start.setting    2011-01-02 23:27:00    set2
17          Start.setting    2011-01-03 00:35:00    set2
18          Start.setting    2011-01-03 01:16:00    set2
19          Start.hauling    2011-01-03 04:31:00   haul2
20          Start.hauling    2011-01-03 08:57:00   haul2

It seems like such a simple question, yet I just cant think of how to
implement this. Any hints or ideas on how I might achieve this would
be much appreciated.

Regards,
Darcy