[R] Reading multiple files from different folders

[PIKAL Petr]

Hi

First you shall move your folders to some other place than c:. Let say

c:\project\country\...

after that you can list folders by ?list.dirs and files by ?list.files.

you can then navigate directories by ?setwd, ?getwd and read files from them.

The exact code depends on what exactly you have and want to do and I wonder if anybody can give canned solution for you, especially when your files have various origin.

Here is a sample of code reading files from folders, calculating some values, plotting some graphs and writing final result.

wd<- getwd()
dirs<-list.dirs()
dirs<-dirs[-1]
n <- length(dirs)
pigm<-gsub("./([[:alnum:]])","\\1", dirs)
vysled <- data.frame(MinFeret=rep(NA, n), ECD = rep(NA, n),
aspect= rep(NA,n), pigment=rep("X", n), stringsAsFactors=F)

for (i in 1:length(dirs)) {

setwd(wd)
setwd(dirs[i])
if(file.exists("Results.xls")) {
velik<-read.delim("Results.xls")
zeros <- which(velik[,c(2,3,7)]<5, arr.ind=T)[,1]
if (length(zeros)>0) velik<-velik[-zeros,]
velik$ecd<-sqrt(4*velik$Area/pi)
velik$aspect<-velik$Feret/velik$MinFeret
velik <- velik[,-1]
maxx<-ceiling(max(velik$ecd)/100)*100

png(paste(pigm[i], "png", sep="."), 800,800)
plot(ecdf(velik$ecd), col=3, main=pigm[i], xlab="Particle size nm",
ylab="Cummulative percentage ECD", xlim=c(0,maxx))
plot(ecdf(velik$MinFeret), col=4, main=pigm[i], xlab="Particle size nm",
ylab="Cummulative percentage MinFeret", xlim=c(0,maxx), add=T)
abline(v=100, h=.5, col="pink", lwd=5)
legend(450, .2, legend=c("ECD", "MinFeret"), fill=3:4)
dev.off()

png(paste(paste(pigm[i], "ECD"), "png", sep="."), 800,800)
plot(ecdf(velik$ecd), col=3, main=pigm[i], xlab="Particle size nm",
ylab="Cummulative percentage ECD", xlim=c(0,maxx))
abline(v=100, h=.5, col="pink", lwd=5)
dev.off()

vysled[i,1:2]<- round(apply(velik[,6:7], 2, median),0)
vysled[i,3]<- round(median(velik[,8]),3)
vysled[i,4] <- pigm[i] } else {
vysled[i,4] <- pigm[i]}
setwd(wd)
write.table(vysled, "vysled.xls", sep="\t", row.names=F, na="")

}

Cheers
Petr

> -----Original Message-----
> From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Val
> Sent: Thursday, August 13, 2015 4:37 AM
> To: r-help at r-project.org
> Subject: [R] Reading multiple files from different folders
>
> Hi all,
>
> I have several files in different folders or subdirectories.  Here is
> an example of the data set.
>
> c:\country\state\city.  There might be more than 500 cities.
>
> **********************************
> c:\country\state\city1
> c:\country\state\city2
> .
> .
> .
> c:\country\state\city500
>
> ***************************
> Cities may keep  the population record either in Excel file or  text
> file  format ( *.xlsx or *.txt)
>
> Each file contains :   first name, last name, address, zip code, etc
>
> I want  to create one data set  from  all the cities  for analysis of
> in interest.
>
> Output should looks  like
>
> country,  state, city, first name, last name, address, zip code,  etc.
>  USA ,    NY ,  city1, Alex    ,    John  ,     102  st name ,   10004
> ,
>  USA   ,     NY ,     city1    Martin  ,         Leno  ,       284
> street
> name  ,  10003 ,
>  .
>  .
>  USA,    NY ,  city500,  Ethan , Noah  ,   543  st name ,  10015 ,
>
> Please note that variables  Country, state and city come from the  "
> c:\country\state\city"
>
> I would appreciate your  help me in reading and combing this data sets
>
> Thank you in advance,
>
>       [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.

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