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
Xuhong Zhu napsal(a):> 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)}This cannot work since paste() gives you quoted character output while functions like data.frame() etc expect a name of some R object. You can use paste when reading individual csv files: for(n in 1:10){ mydata <- read.csv(file=paste('...STA6704/pat',n,'.csv',sep=""), header = TRUE, sep = ",", quote = "", fill = TRUE) # ... further lines to process mydata ... } A faster way of computing would involve reading the individual files into a list of dataframes and using lapply() on that list rather than processing the data inside the loop. Petr> Xuhong >-- Petr Klasterecky Dept. of Probability and Statistics Charles University in Prague Czech Republic
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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