[R] how to edit my R codes into a efficient way

[Bert Gunter]

Have you read An Introduction to R? If not, do so before posting any further
questions.

Once you have read it, pay attention to what it says about lists, which is a
very general data structure (indeed, **the** most general) that is very
convenient for this sort of task. The general approach that one uses is
something like:

ContentsOfFiles <- lapply(filenameVector,
functionThatReadsFile,additionalParametersto Function)

More specifically,

ContentsOfFiles <- lapply(filenameVector, read.csv, header=TRUE,
quote="",fill=TRUE)

see ?lapply


Bert Gunter
Genentech Nonclinical Statistics
South San Francisco, CA 94404
650-467-7374


-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Xuhong Zhu
Sent: Tuesday, March 06, 2007 7:19 AM
To: r-help at stat.math.ethz.ch
Subject: [R] how to edit my R codes into a efficient way

Hello, Everyone,

I am a student an a new learner of R and I am trying to do my homework
in R. I have 10 files need to be read and process seperately. I really
want to write the codes into something like "macro" to save the lines
instead of repeating 10 times of similar work.

The following is part of my codes and I only extracted three lines for
each repeating section.


data.1 <- read.csv("http://pegasus.cc.ucf.edu/~xsu/CLASS/STA6704/pat1.csv",
header = TRUE, sep = ",", quote = "",
fill = TRUE);
data.2 <- read.csv("http://pegasus.cc.ucf.edu/~xsu/CLASS/STA6704/pat3.csv",
header = TRUE, sep = ",", quote = "",
fill = TRUE);
data.3 <- read.csv("http://pegasus.cc.ucf.edu/~xsu/CLASS/STA6704/pat4.csv",
header = TRUE, sep = ",", quote = "",
fill = TRUE);

baby.1 <- data.frame(cuff=data.1$avg_value,
time=seq(1,dim(data.1)[1]), patient=rep(1, dim(data.1)[1]))
baby.2 <- data.frame(cuff=data.2$avg_value,
time=seq(1,dim(data.2)[1]), patient=rep(3, dim(data.2)[1]))
baby.3 <- data.frame(cuff=data.3$avg_value,
time=seq(1,dim(data.3)[1]), patient=rep(4, dim(data.3)[1]))


I also tried the codes below but it doesn't work.

for(n in 1:10){
mm <- data.frame(cuff=paste("data",n, sep=".")$avg_value,
time=seq(1,dim(paste("data",n, sep="."))[1]),
patient=rep(1,paste("data",n, sep="."))[1]))
assign(paste("baby",n,sep="."), mm)}

I am looking forward to your help and thanks very much!

Xuhong

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