R help - Jul 2010 - conditional dataframe search and find

After some processing...
   ct.df    <- data.frame(time,conc)
   ct.df
   gives
      time       conc
   1     0 164.495456
   2     1 133.671185
   3     2 108.622975
   4     3  88.268468
   5     4  71.728126
   6     5  58.287225
   7     6  47.364971
   8     7  38.489403
   9     8  31.276998
   10    9  25.416103
   11   10  20.653462
   12   11  16.783276
   13   12  13.638313
   14   13  11.082674
   15   14   9.005927
   16   15   7.318336

- Ignored:
   17   16   5.946977
   18   17   4.832592
   19   18   3.927028
   20   19   3.191155
   21   20   2.593175
   22   21   2.107248
   23   22   1.712378
   24   23   1.391501
   25   24   1.130752

   I need to find the time when conc < 25. I can read it off the table but I
am

   looking for a programmatic solution.

   Thanks.
   Oscar


-- 
Oscar A. Linares, MD
Clinical Assistant Professor of Medicine
Department of Medicine
University of Toledo College of Medicine
Toledo, Ohio 43606-3390

Attending Physician
The Detroit Medical Center (DMC)
Harper University Hospital
Wayne State University School of Medicine
Detroit, Michigan 48201

Director
Translational Pharmacokinetics & Pharmacogenomics Unit,
La Plaisance Bay, Bolles Harbor, MI

Medical Director
Monroe Pain Center
Monroe, MI 48162
(http:www.monroepaincenter.com)

Phone (734) 240-8400
Cell (734) 637-7997
Fax (734) 243-6254

oalinaresmd@gmail.com

	[[alternative HTML version deleted]]

> ct.df[ct.df$conc < 25,"time"]
[1] 10 11 12 13 14 15
 > ct.df[ct.df$conc < 25,"time"][1]
 > df[df$conc < 25,"time"][1]
[1] 10

See also help("order") if conc is not ordered.

On 02/07/10 22:50, oscar linares wrote:
>        time       conc
>     1     0 164.495456
>     2     1 133.671185
>     3     2 108.622975
>     4     3  88.268468
>     5     4  71.728126
>     6     5  58.287225
>     7     6  47.364971
>     8     7  38.489403
>     9     8  31.276998
>     10    9  25.416103
>     11   10  20.653462
>     12   11  16.783276
>     13   12  13.638313
>     14   13  11.082674
>     15   14   9.005927
>     16   15   7.318336
>