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Basic Problem with Data Input

3 messages · Walter Niessen, Sarah Goslee, Ben Tupper

Original
Walter Niessen
# 
Helpers,

I am a pretty savvy computer user (over 40 years) but am having trouble with the most basic process in using the R program.  I am taking a course to learn the statistics utility of ?R? but can?t seem to get past the opening where it shows the student how to input data into R.

It suggests identifying as the a target folder in the Properties of the R x64 3.2.3 icon (I use a 64-bit Windows 7 OS) the location where data files are found. I entered: 

As the Target:  "C:\Program Files\R\R-3.2.3\bin\x64\Rgui.exe"  ... which contains Rgui.exe and the supporting dlls etc.

As the Start in: "C:\Program Files\R\R-3.2.3\Appendix" ... where Appendix is a folder which contains data files such as the text file DATA1.txt which I created from an Excel file.

When I try and get R to input the data, I get the following sequence of messages:
Error in file(file, "r") : cannot open the connection
In addition: Warning message:
In file(file, "r") :
  cannot open file 'DATA1.txt': No such file or directory

When I try again but use the complete file description, I get:

X=scan("C:\Program Files\R\R-3.2.3\Appendix\DATA1.txt")
Error: '\P' is an unrecognized escape in character string starting ""C:\P"

I hate to ask a question not related to R or its features (that may come later), but, clearly, the first baby step is to be able to load data into the application . . . and, I am really frustrated with my inability to do so.  I apologize for this but really need to get past this business to jump into the REAL use of R.

Can you help?

Walt

Walter R. Niessen
(978) 470-4622

P.S. I apologize, but I sent the first ?edition? a few minutes ago without a Subject and not quite finished up.
Sarah Goslee
# 
Hi Walter,

I'm not sure changing the shortcut properties are the best approach.
Instead, after you start R, you can use the
getwd()
command to see where R will start looking for things, and the
setwd()
command to change that (wd is working directory).

Because of the way R parses strings, you either need to use double
backslashes or single forward slashes if you want to specify a full
path:
X <- scan("C:\\Program Files\\R\\R-3.2.3\\Appendix\\DATA1.txt")
X <- scan("C:/Program Files/R/R-3.2.3/Appendix/DATA1.txt")
will both work.

Here's a basic overview of the relevant material:
http://www.dummies.com/how-to/content/how-to-work-with-files-and-folders-in-r.html

It's perhaps not the most logical place to look, but it's also in the
R Windows FAQ as number 2.16:
https://cran.r-project.org/bin/windows/base/rw-FAQ.html

Sarah
On Sun, Feb 7, 2016 at 3:23 PM, Walter Niessen <niessen at att.net> wrote:
Ben Tupper
# 
Hi,

Using the full path specification, as you have done in your second example, is a good idea.   Have you tried forward slashes?  If I am reading the docs correctly you should be able to use either forward or back slashes.  I haven't used R in Windows for ages, but my memory is that switching to forward slashes skirted any troublesome issues.  Try this...

filename <- "C:/Program Files/R/R-3.2.3/Appendix/DATA1.txt"
if (file.exists(filename)){
	X <- scan(file = filename, what = double())
} else {
	cat('file not found\n')
}

Here's the doc page...

https://cran.r-project.org/doc/manuals/r-release/R-intro.html#OS-facilities

Ben
Ben Tupper
Bigelow Laboratory for Ocean Sciences
60 Bigelow Drive, P.O. Box 380
East Boothbay, Maine 04544
http://www.bigelow.org