I'm new to functions and I would like to load my data with a function.
The function appears to be correct but the file does not save as a dataframe to the environment, while this does happen when it's not within the function.
This is my script:
read_testdata <- function(file) {
Dataset_test <- read_rds(here("foldername", file))
}
read_testdata("filename")
Can someone spot my error?
After some thinking I spotted my problem, the correct code should be this:
read_testdata <- function(file) {
read_rds(here("foldername", file))
}
Dataset_test <- read_testdata("filename.rds")
Related
eem_import_dir is supposed to "Reads Rdata and RDa files with one eemlist each. The eemlists are combined into one and returned." However, in my case, only one file is read at the time, and thus no combination is happening...
I don't expect any error in the function which is part of the staRdom package. I guess my limited R knowledge limits my understanding of the function and what could be wrong.
All files are the same class (eemlist) and in the same format. Tried changing the folder, filenames, etc. Can someone please help me understand the requirements of the function? Why is only one file read at the time and not all combined?
function (dir)
{
eem_files <- dir(dir, pattern = ".RData$|.RDa$", ignore.case = TRUE) %>%
paste0(dir, "/", .)
for (file in eem_files) {
file <- load(file)
if (get(file) %>% class() == "eemlist") {
if (exists("eem_list"))
eem_list <- eem_bind(eem_list, get(file))
else eem_list <- get(file)
}
else {
warning(paste0(file, " is no object of class eemlist!"))
}
NULL
}
eem_list
}
I am trying to read 23 excel files, store each in a list, and then rbind them to one csv. Some of these file are csv and some of them are xlsx. However, I got the following message:
Error: Can't establish that the input is either xls or xlsx.
So I want to identify which ones are giving error and then append it manually.
My function is the following:
make_df<-function(filename){
library(readxl)
library(foreign)
if (str_sub(filename,-3,-1) == "csv"){
df<-read.csv(filename,fileEncoding="latin1")
}
else{
df<-read_excel(filename)
}
return(df)
}
filenames_vector<-list.files(# directory)
datalist = list()
for (i in 1:23){
datalist[[i]] <- make_df(filenames_vector[i])
}
mega_data = do.call(rbind,datalist)
How can I add something in make_df to print out the names of files that are causing the error message? Also, is there another work around, when the the error message is on not being able to distinguish xlsx from xls?
This can be done with a tryCatch block. Without example data it's a little hard to recreate. I'm not sure what you mean in your second question.
Try the code below to catch errors and print out the filename if there's an error, otherwise return the df object.
make_df<-function(filename){
library(readxl)
library(foreign)
df = tryCatch(
{ # try block
if (str_sub(filename,-3,-1) == "csv"){
df<-read.csv(filename,fileEncoding="latin1")
}
else{
df<-read_excel(filename)
}
},
error=function(cond){return(filename)} # grab the filename if there was an error
)
if (class(df) == 'character') {
print(df)
} else{return(df)}
}
I have a function readTochens which is to read csv files. I want to loop through a few more files. the following is the code and it doesn't work. Error message is that No Such file or direction. Any suggestions?
dir <- c("allfac12","allfac13")
cpas <- c("cpas12","cpas13")
mainloop <- function(){
for(i in 1:length(dir)){
readTochens(as.name(dir[i]),as.name(cpas[i]))
}
}
mainloop()
I need to create a function in R that reads all the files in a folder (let's assume that all files are tables in tab delimited format) and create objects with same names in global environment. I did something similar to this (see code below); I was able to write a function that reads all the files in the folder, makes some changes in the first column of each file and writes it back in to the folder. But the I couldn't find how to assign the read files in to an object that will stay in the global environment.
changeCol1 <- function () {
filesInfolder <- list.files()
for (i in 1:length(filesInfolder)){
wrkngFile <- read.table(filesInfolder[i])
wrkngFile[,1] <- gsub(0,1,wrkngFile[,1])
write.table(wrkngFile, file = filesInfolder[i], quote = F, sep = "\t")
}
}
You are much better off assigning them all to elements of a named list (and it's pretty easy to do, too):
changeCol1 <- function () {
filesInfolder <- list.files()
lapply(filesInfolder, function(fname) {
wrkngFile <- read.table(fname)
wrkngFile[,1] <- gsub(0, 1, wrkngFile[,1])
write.table(wrkngFile, file=fname, quote=FALSE, sep="\t")
wrkngFile
}) -> data
names(data) <- filesInfolder
data
}
a_list_full_of_data <- changeCol1()
Also, F will come back to haunt you some day (it's not protected where FALSE and TRUE are).
add this to your loop after making the changes:
assign(filesInfolder[i], wrkngFile, envir=globalenv())
If you want to put them into a list, one way would be, outside your loop, declare a list:
mylist = list()
Then, within your loop, do like so:
mylist[[filesInfolder[i] = wrkngFile]]
And then you can access each object by looking at:
mylist[[filename]]
from the global env.
The following code works:
Name<-"s1521r0000_rd2.txt"
OneFile<-read.table(file=Name, sep="", skip=35, fill=TRUE )
But, I am trying to write a function that will load one .txt file so that I can load whatever .txt file I want. I wrote the following function which is not working:
ReadOneFile<-function(Name="s1521r0000_rd2.txt"){
OneFile<-read.table(file=Name, sep="", skip=35, fill=TRUE )
}
It would be great if you could help me.
You need to return() the file from the function into an object. For instance:
func.readonefile <- function(Name) {
thefile <- read.table(file=Name,sep="",skip=35,fill=TRUE)
return(thefile)
}
a_file <- func.readonefile(Name="s1521r0000_rd2.txt")