problem creating dynamic file name in R - r

I'm working on a script in R that processes some data and writes an output file. I'd like that output file to be named in a way that reflects the input file, and I'd like something about the file to be unique so older files aren't overwritten.
So I thought to use a timestamp. But this isn't working the way I'd hoped, and I'd like to understand what's happening and how to do this correctly.
This is how I'm trying to name the file (file_base is the name of the input file):
now<-format(Sys.time(), "%b%d%H%M%S")
outputfile<-cat(file_base, "-",now,"-output.txt", sep="")
The output of this pair of functions looks great. But executing 'outputfile' subsequently results in 'NULL' as output.
What's happening here and how can I create an output filename with the properties that I'd like?

You're confusing cat and paste. You want:
outputfile <- paste(file_base, "-",now,"-output.txt", sep="")

You can also use the function sprintf(), it's a wrapper for the C function.
example:
filepath <- file.path(outdir, sprintf("abcdefg_%s.rda", name))

You could also use the separator argument of paste:
outputfile <- paste(file_base,now,"output.txt", sep="-")

Related

Specify path in write.csv function

I have a simple syntax question: Is there a way to specify the path in which to write a csv file within the .csv function itself?
I always do the following:
setwd("C:/Users/user/Desktop")
write.csv(dt, "my_file.csv", row.names = F)
However, I would like to skip the setwd() line and include it directly in the write.csv() function. I can't find a path setting in the write.csv documentation file. Is it possible to do this exclusively in write.csv without using write.table() or having to download any packages?
I am writing around 300 .csv files in a script that runs auomatically everyday. The loop runs slower when using write.table() than when using write.csv(). The whole reason I want to include the path in the write.csv() function is to see if I can decrease the time it takes to execute any further.
I typically set my "out" path in the beginning and then just use paste() to create the full filename to save to.
path_out = 'C:\\Users\\user\\Desktop\\'
fileName = paste(path_out, 'my_file.csv',sep = '')
write.csv(dt,fileName)
or all within write.csv()
path_out = 'C:\\Users\\user\\Desktop\\'
write.csv(dt,paste(path_out,'my_file.csv',sep = ''))
There is a specialized function for this: file.path:
path <- "C:/Users/user/Desktop"
write.csv(dt, file.path(path, "my_file.csv"), row.names=FALSE)
Quoting from ?file.path, its purpose is:
Construct the path to a file from components in a platform-independent way.
Some of the few things it does automatically (and paste doesn't):
Using a platform-specific path separator
Adding the path separator between path and filename (if it's not already there)
Another way might be to build a wrapper function around the write.csv function and pass the arguments of the write.csv function in your wrapper function.
write_csv_path <- function(dt,filename,sep,path){
write.csv(dt,paste0(path,filename,sep = sep))
}
Example
write_csv_path(dt = mtcars,filename = "file.csv",sep = "",path = ".\\")
In my case this works fine,
create a folder -> mmult.datas
copy its directory-> C:/Users/seyma/TP/tp.R/tp.R5 - Copy
give a name of your .csv -> df.Bench.csv
do not forget the write your data.frame -> df
write.csv(df, file ="C:/Users/seyma/TP/tp.R/tp.R5 - Copy/mmult.datas/df.Bench.csv")
for more you can check the link

How to read results from one R script to another

Is there anyway I can store the results of one variable in one R script, and make them available to another R script?
I have this basic script in one file:
B5b=fit(y~.,d_treino_both,model="randomforest",task="class")
P5b=predict(B5b,d_teste)
x=d_teste$y
m5b=mmetric(x,P5b,metric=c("ACC","ACCLASS","CONF", "ROC"))
mgraph(x,P5b,graph= "ROC", baseline=TRUE)
print(m5b)
P5b
Then, I want to make the resuts of P5b variable available to another script.
Any help?
Not sure if this is what you are looking for. I think one way you can do that is to source the script1 in script2. I would do something like this and remove any additional variables using rm.
source("script1.R")
Perhaps you could try something with dput and the clipboard. Basically, this is just copying the dput of an object to the clipboard and then evaluating the clipboard in the second script. Note that you cannot use the clipboard in the meantime.
# first script
obj <- capture.output(dput(matrix(1:100, 10, 10)))
writeClipboard(str = obj)
# second script
obj2 <- eval(parse(text = readClipboard()))

How to create a new read.csv in R so it can read .csv file without typing the full name of .csv file

guys, thanks for read this. This is my first time writing a program so pardon me if I make stupid questions.
I have bunch of .csv files named like: 001-XXX.csv;002-XXX.csv...150-XXX.csv. Here XXX is a very long name tag. So it's a little annoying that every time I need to type read.csv("001-xxx.csv"). I want to make a function called "newread" that only ask me for the first three digits, the real id number, to read the .csv files. I thought "newread" should be like this:
newread <- function(id){
as.character(id)
a <- paste(id,"-XXX.csv",sep="")
read.csv(a)
}
BUt R shows Error: unexpected '}' in "}" What's going wrong? It looks logical.
I am running Rstudio on Windows 8.
as.character(id) will not change id into a character string. Change it to:
id = as.character(id)
Edit: According to comments, you should call newread() with a character paramter, and there is no difference between newread(001) and newread(1).
This is not specifically an answer to your question (others have covered that), but rather some advice that may be helpful for accomplishing your task in a different way.
First, some of the GUI's for R have file name completion. You can type the first part: read.csv("001- and then hit a key or combination of keys (In the windows GUI you press TAB) and the rest of the filename will be filled in for you (as long as it is unique).
You can use the file.choose or choose.files functions to open a dialog box to choose your file using the mouse: read.csv(file.choose()).
If you want to read in all the above files then you can do this in one step using lapply and either sprintf or list.files (or others):
mycsvlist <- lapply( 1:150, function(x) read.csv( sprintf("%03d-XXX.csv", x) ) )
or
mvcsvlist <- lapply( list.files(pattern="\\.csv$"), read.csv )
You could also use list.files to get a list of all the files matching a pattern and then pass one of the returned values to read.csv:
tmp <- list.files(pattern="001.*csv$")
read.csv(tmp[1])

Reading a file in, then writing out a file with similar name in R

In R, I would like to read in data from a file, then do a bunch of stuff, then write out data to another file. I can do that. But I'd like to have the two files have similar names automatically.
e.g. if I create a file params1.R I can read it in with
source("c:\\personal\\consults\\ElwinWu\\params1.R")
then do a lot of stuff
then write out a resulting table with write.table and a filename similar to above, except with output1 instead of params1.
But I will be doing this with many different params files, and I can foresee making careless mistakes of not changing the output file to match the params file. Is there a way to automate this?
That is, set the number for output to match the number for params?
thanks
Peter
If your source file always contains "params" which you want to change to "output" then you can easilly do this with gsub:
source(file <- "c:\\personal\\consults\\ElwinWu\\params1.R")
### some stuff
write.table(youroutput, gsub("params","output",file) )
# Will write in "c:\\personal\\consults\\ElwinWu\\output1.R"
Edit:
Or to get .txt as filetype:
write.table(youroutput, gsub(".R",".txt",gsub("params","output",file)))
# Will output in c:\\personal\\consults\\ElwinWu\\output1.txt"
Edit2:
And a loop for 20 param files then would be:
n <- 20 # number of files
for (i in 1:n)
{
source(file <- paste("c:\\personal\\consults\\ElwinWu\\params",i,".R",sep=""))
### some stuff
write(youroutput, gsub(".R",".txt",gsub("params","output",file)))
}
If the idea is just to make sure that all the outputs go in the same directory as the input then try this:
source(file <- "c:\\personal\\consults\\ElwinWu\\params1.R")
old.dir <- setwd(dirname(file))
write.table(...whatever..., file = "output1.dat")
write.table(...whatever..., file = "output2.dat")
setwd(old.dir)
If you don't need to preserve the initial directory you can omit the last line.

R: read contents of text file as a query?

Using R, I just want to read the contents of a file into a variable like:
query <- read_file_contents('biglongquery.sql')
As to avoid putting, well, big long queries in the R script itself. I do not want to read in data like CSV (e.g. read.tables), etc- just the raw text.
Scan does the job, but the function for this purpose is actually readLines().
query <- readLines("biglongquery.sql")
This gives you a vector with the lines. To combine them to one single variable, you can use the paste function, e.g.
one.variable <- paste(query,collapse="\n")
x <- paste(scan("foo.sql",what="",sep="\n",blank.lines.skip=FALSE),collapse="\n")
Another way is to create a .R script with query definition
# content of biglongquery.R
query <- "
SELECT
very_long_list_of_fields
FROM ...
"
and then use it in the main script using
source("biglongquery.R")

Resources