[R] Turnpoints

[David Winsemius]

On Sep 16, 2009, at 1:42 PM, ogbos okike wrote:

> Good evening to everybody. I have a data of four columns - three of  
> the
> columns represent date while the fourth is counts.  Setting 4000 as my
> minimum point/value, I wish to find out the number of counts that  
> are less
> or equal to 4000


You already have two good worked solutions from Steve Lianoglou for the
second part. I find table(<logical expression>) to be a useful  
construct.

 > ct <- read.table(textConnection("y  m   d  count
+ 93 02 07 3974.6
+ 93 02 08 3976.7
+ 93 02 09 3955.2
+ 93 02 10 3955.0
+ 93 02 11 3971.8
+ 93 02 12 3972.8
+ 93 02 13 3961.0
+ 93 02 14 3972.8
+ 93 02 15 4008.0
+ 93 02 16 4004.2
+ 93 02 17 3981.2
+ 93 02 18 3996.8
+ 93 02 19 4028.2
+ 93 02 20 4029.5
+ 93 02 21 3953.4
+ 93 02 22 3857.3
+ 93 02 23 3848.3
+ 93 02 24 3869.8
+ 93 02 25 3898.1
+ 93 02 26 3920.5
+ 93 02 27 3936.7
+ 93 02 28 3931.9"), header=T)

 > table(ct$count <= 4000)

FALSE  TRUE
     4    18

> and the dates they occur. I have installed pastecs and have
> been trying to use turnpoints function to do this. I have not been  
> much
> lucky. I am a still learning. I have added part of my data here  
> where y
> stands for year, m month, d day and lastly the count.
> I would be grateful to anyone who could show me the way the do this.
> Best regards
> Ogbos
>

-- 
David Winsemius, MD
Heritage Laboratories
West Hartford, CT