QFile::rename description says:
If the rename operation fails, Qt will attempt to copy this file's
contents to newName, and then remove this file, keeping only newName.
That is undesirable. I need to call QFile::rename only if the file can be renamed without copying (e. g. remains on the same disk drive on Windows). Is there a function in Qt that can perform this check (without me having to code it manually for every platform)?
I've ended up getting and checking the drive number on Windows (PathGetDriveNumber) and drive ID on Unix (stat function and st_dev field of the stat structure). Seems to work as expected so far.
Related
I used to work with R on my mac and never had any problems.
Now I would like to use it on my work computer (windows). The problem is I can't import any files to start working with them. I tried several options:
mydata<-read.table("c:/temp/myfile.csv",header=TRUE)
mydata<-read.csv("myfile.csv",header=TRUE)
mydata<-read.table("c:/myfile.csv",header=TRUE)
mydata<-read.table("Desktop/myfile.csv",header=TRUE)
I also tried to change / into \ in all variants above.
Nothing seems to work. R displays the command in red, sometimes with a comment "connection can't be opened" or "no such file or directory" (my translation from German).
I tried copying the file I want to open to a different location (desktop, c:, temp), but alas, nothing helps.
Do you have any ideas why I have this problem and how I can solve it? Thanks in advance.
There is a safer way to work with paths; just using file.path().
So, if you're trying to get a file in C:/temp/turtles.csv, then you'd use:
targetFile <- file.path('C:/', 'temp', 'turtles.csv')
read.csv( targetFile, header=TRUE )
Minor point since it showed up on Twitter; DO NOT USE PATHS THAT EXIST ONLY IN YOUR ENVIRONMENT.
Try to keep the data in a path either in or directly under where the script is.
You have three ways to do this with read.csv() function
To avoid inserting actual path you can do it simply nesting function
read.csv(file.choose(),header=TRUE)
it will open pop up for selecting your file just select file from directory
where you have saved it.
Now if you have to insert a path then just get actual location of your file
by
read.csv("C:\path\to\your\file\filename.csv",header=TRUE)
for Example
read.csv("C:\Users\Amway\Desktop\resources.csv",header=TRUE)
Best way is to have your own work space directory
so create a directory by your preferred name and just set that directory as a
R session work space by
setwd("C:\path\to\your\workspace directory\")
check your current directory by
getwd()
now if you want to read a file into R session just copy your file to work
space and just write
read.csv("resources.csv",header=TRUE)
So, it should be like this.
setwd("c:/mydir") # note / instead of \ in windows
Also.
MyData <- read.csv(file="c:/mydir/TheDataIWantToReadIn.csv", header=TRUE, sep=",")
Windows uses the other backslash.
https://www.howtogeek.com/181774/why-windows-uses-backslashes-and-everything-else-uses-forward-slashes/
I am using R Studio and I want to save my script (i.e., the upper left panel). However, the only ways that I can find to do it are by either clicking the blue floppy disk icon to save or using the drop down menu File > Save > name.R
Is there any way besides using these shortcuts to save the script to a .R file or is the shortcut the only way?
Thanks.
You can use rstudioapi::documentSave() to save the currently open script file to disk.
From the source documentation, one can see that it can be used in conjunction with the id returned with getActiveDocumentContext()$id to make sure the document saved is the one running the script.
For your intended use, try:
rstudioapi::documentSave(rstudioapi::getActiveDocumentContext()$id)
For future reference, here is the reference manual of rstudioapi:
https://cran.rstudio.com/web/packages/rstudioapi/rstudioapi.pdf
I'm not yet allowed to comment, but this refers to the comment above that this does not work with .rmd files:
rstudioapi::documentSave(rstudioapi::getActiveDocumentContext()$id)
I tried and in Rstudio Version 1.2.5042 it does seem to work.
Every new tab in R(created by ctrl+shift+n) can be independently saved by using ctrl+s in the respective tab. If you intend to rename the file though, you may do it as you would rename any file in windows(goto the file location and single click on the filename). Hope my answer was of some help!
Situation
I wrote an R program which I split up into multiple R-files for the sake of keeping a good code structure.
There is a Main.R file which references all the other R-files with the 'source()' command, like this:
source(paste(getwd(), dirname1, 'otherfile1.R', sep="/"))
source(paste(getwd(), dirname3, 'otherfile2.R', sep="/"))
...
As you can see, the working directory needs to be set correctly in advance, otherwise, this could go wrong.
Now, if I want to share this R program with someone else, I have to pass all the R files and folders in relative order of each other for things to work. Hence my next question.
Question
Is there a way to replace all the 'source' commands with the actual R script code which it refers to? That way, I have a SINGLE R script file, which I can simply pass along without having to worry about setting the working directory.
I'm not looking for a solution which is an 'R package' (which by the way is one single directory, so I would lose my own directory structure). I simply wondering if there is an easy way to combine these self-referencing R files into one single file.
Thanks,
Ok I think you could use something like scaning all the files and then writting them again in the same new one. This can be done using readLines and sink:
sink("mynewRfile.R")
for(i in Nfiles){
current_file = readLines(filedir[i])
cat("\n\n#### Current file:",filedir[i],"\n\n")
cat(current_file, sep ="\n")
}
sink()
Here I have supposed all your file directories are in a vector filedir with length Nfiles, I guess you can adapt that
In order to ease the manual copying of large file amounts, I often use FreeFileSync. I noticed that it preserves the original file information such as when a file was created, last modified etc.
Now I need to regularly copy tons of files in batch mode and I'd like to do it in R. So I wondered if R is capable of preserving that information as well. AFAIU, file.rename() and file.copy() alter the file information, e.g. the times are set to the time the files were actually copied.
Is there any way I can restore the original file information after the files have been copied?
Robocopy via system2() can keep the timestamps.
> cmdArgs<- paste( normalizePath( file.path(getwd()), winslash="/"),
normalizePath( file.path(getwd(), "bkup"), winslash="/" ),
"*.txt",
"/copy:DAT /V" )
> system2( "robocopy.exe", args=cmdArgs )
Robocopy has a slew of switches for all different types of use cases and can accept a 'job' file for the params and file names. The ability of R to call out using system could also be used to execute an elevated session (perhaps the easiest would be by using a powershell script to call Robocopy) so that all of the auditing info (permissions and such) could be retained as well.
What is the correct method for enter data(d=read.table("WHAT GOES HERE IF YOU HAVE A MACBOOK ") if you have a mac computer?
Also what does the error code list below mean:
d=read.table(“Firststatex.notepad”,header=T)
Error: unexpected input in "d=read.table(‚"
Two usage errors:
You don't use data() to read in to R datasets held in external files. data() is an R function to load datasets that are built in to R and R packages. read.table("foo.txt") will return a data frame object from the file "foo.txt", which you can assign to an object within R using the assignment operator <-, e.g.
DF <- read.table("foo.txt")
As for "what goes here...", you need to supply a file system path from the current directory to the directory holding the file you want to read in. If the file "foo.txt" is in the current working directory, you can just provide the file name with extension as I did above. If the file is in another directory you need to supply the path to the file name and the file name, for example if the file "foo.txt" is located in the directory above the current directory, you would supply "../foo.txt". If it were in a directory myData located in the directory above the current directory you could us "../myData/foo.txt". So paths can be relative to the current directory. You can also use the fully qualified path on your file system hierarchy.
An alternative is to use the file.choose() function in place of the file name string. This will allow you to navigate to the file you wish to load interactively using a native file selection dialogue. This is what happens on Windows and I suspect also on Mac; not much different happens on Linux. For example:
DF <- read.table(file.choose())
You should probably look for specific help for your operating system if you are not familiar with how to specify file names and paths.
I get the same error when copying and pasting in the code you provide. The problem comes from the fact that you are using fancy, curly quotes “Firststatex.notepad” rather than one of the three sets of accepted quote marks: ` , ", and '; each of these is acceptable, i) "Firststatex.notepad", ii) 'Firststatex.notepad', and iii) `Firststatex.notepad` Just because the quotes you used look like quotes to you or I, these aren't quotes as far as most computer programs recognise. MS Word often inserts these quotes when you enter " for example, as do many other applications.