CODEWITHSUNDEEP
rfor-looperror-handling
user2654764
user2654764

Reputation: 1829

I'm trying to skip over errors and warnings in this for loop in r but its not working?

I am trying to read csv files with their names as dates into a for loop and then print out a few columns of data from that file when it is actually there. I need to skip over the dates that I don't have any data for and the dates that don't actually exist. When I put in my code there is no output, it is just blank. Why doesn't my code work?

options(width=10000)

options(warn=2)

for(a in 3:5){
for(b in 0:1){
for(c in 0:9){
for(d in 0:3){
for(e in 0:9){

mydata=try(read.csv(paste("201",a,b,c,d,e,".csv",sep="")), silent=TRUE)

if(class(mydata)=="try-error"){next}

else{

    mydata$Data <- do.call(paste, c(mydata[c("LAST_UPDATE_DT","px_last")], sep=""))
    print(t(mydata[,c('X','Data')]))
}

}}}}}

Upvotes: 0

Views: 149

Answers (1)

Hong Ooi
Hong Ooi

Reputation: 57686

That's a really terrible way to read in all your files. Try this:

f <- list.files(pattern="*.csv")
mydata <- sapply(f, read.csv, simplify=FALSE)

This will return a list mydata of data frames, each of which is the contents of the corresponding file.

Or, if there are other csv files that you don't want to read in, you can restrict the specification:

f <- list.files(pattern="201\\d{5}\\.csv")

And to combine everything into one big data frame:

do.call(rbind, mydata)

Upvotes: 1

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