Hi!
I would extract the minutes from the time using sub (see ?sub) or (?grep)
than use them as factors (?as.factors)
and finally
?tapply
eg.
tt<-1:10
fac<-c(rep(0,4),rep(1,6)) # here put the minutes from the time
fac
[1] 0 0 0 0 1 1 1 1 1 1
fac<-as.factor(fac)
fac
[1] 0 0 0 0 1 1 1 1 1 1
Levels: 0 1
tapply(t,fac,max)
0 1
4 10
Sincerely Eryk.
*********** REPLY SEPARATOR ***********
On 5/26/2004 at 3:00 PM solares at unsl.edu.ar wrote:
>Hi, i need select data from data frame, for example:
>x is a data frame with values in jump to 5 seconds
>12:10:00 51 //one minute
>12:10:05 63
>12:10:10 75
>12:10:15 88
>..
>12:10:59 45
>12:11:00 46 //another minute
>12:11:05 11
>..
>Have a command what to select the data minute to minute, for example
>in the example above i need the maximun values minute to minute
>1?? minute-->88
>2?? minute--> 46
>Thanks Ruben
>
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Dipl. bio-chem. Eryk Witold Wolski @ MPI-Moleculare Genetic
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