# [R] For loop for subset - repeating same over and over?

Dennis Murphy djmuser at gmail.com
Fri Sep 30 12:14:27 CEST 2011

```Hi:

This would be a lot easier to check with a reproducible example, but
here's a simplified version of your problem:

each = 15),
trt = rep(LETTERS[1:3], each = 5),
y = rnorm(75))
testd\$gps <- as.character(testd\$gps)
str(testd)

library('plyr')
# The subset is handled by the grouping variable gps:
mlist <- dlply(testd, .(gps), function(d) aov(y ~ trt, data = d))
# Apply the summary function to each groupwise ANOVA:
llply(mlist, summary)

# Equivalent approach:
# splitting the data by gps is equivalent to use of the grouping
variable in dlply()
mlist2 <- lapply(split(testd, testd\$gps), function(d) aov(y ~ trt, data = d))
llply(mlist2, summary)

Is that what you had in mind?

Dennis

On Thu, Sep 29, 2011 at 4:37 PM, kelseyann <kremerke at mail.gvsu.edu> wrote:
> Hello, I am using the following script to run an anova for numerous species
> in a table that I have:
>
>
> SiteSpp <-
>
> n.SiteSpp <- length(SiteSpp)
>
>  for (i in (1:n.SiteSpp)) {
>      QInfl.aov <- aov(AvgOfnumResponse ~ strTrea*strYear,
> data=QInflAvgbyPlot, subset=(SiteSpp == SiteSpp[i]))
>      print(summary(QInfl.aov))
>  }
>
>
> The resulting summary just continuously prints the same anova results (For
> ADHALP) over and over again.... Any suggestions?
>
> Thanks,
> Kelsey
>
> --
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>
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