Dear All,
I have a database of 200 observations named myD.
In the dataframe there are a column named code (with codes varying from 1 to
77), a column named "prevalence" with some quantitative measurements are given
and an column named Pr_mean, with no values.
I would like to set a cycle to compute the average of prevalence values for
each different code and store the averages under the empty field Pr_mean.
This is what I wrote:
# Set a cycle
for (i in 1:nrow(myD)) {
mycode = myD$code[i]
mymean[i] = mean(prevalence)
myD$Pr_mean[i] = mymean[i]
}
With the above cycle I am able to compute the average of all 200 observations
which is then written in every cell.
I understand that a condition is missing, that indicates that the average has
to be computed amongst the observations showing the same codes values.
Could you please help me ?
D.
Posta, news, sport, oroscopo: tutto in una sola pagina.
Crea l'home page che piace a te!
www.yahoo.it/latuapagina
[[alternative HTML version deleted]]
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
