Message-ID: <12D0D00E1404D511A4820090274CA09C02FC059F@dasmtyjqf010.amedd.army.mil>
Date: 2003-05-30T19:38:56Z
From: White, Charles E WRAIR-Wash DC
Subject: Extracting Vectors from Lists of Lists Produced by Functions
If you found my subject heading to be confusing then I'm sure you'll enjoy
the example I've included below. I find the apply type functions to be
wonderful for avoiding loops but when I use them with existing functions, I
end up using loops anyway to extract the vectors I want. I would appreciate
it if someone could show me how to avoid these loops. Thanks.
EXAMPLE:
noise<-matrix(data = rnorm(15, mean=0, sd=1), nrow = 5, ncol = 3,
byrow = FALSE, dimnames = NULL)
measure<-apply(noise,2,t.test)
measure
tval<-NULL
df<-NULL
pval<-NULL
for (i in 1:length(measure)){
tval[i]<-measure[[i]][[1]]
df[i]<-measure[[i]][[2]]
pval[i]<-measure[[i]][[3]]}
data.frame(tval,df,pval)
Charles E. White, Biostatistician
Walter Reed Army Institute of Research
503 Robert Grant Ave., Room 1w102
Silver Spring, MD 20910-1557
301 319-9781
WRAIR Home Page: http://wrair-www.army.mil/