how to define variables after importing excel sheet in R - r

i imported exel to R now i do not know how to solve the question, as it is my 1st time with R

As this looks like an assignment/homework question, and you mention this is your 1st time with R, I think you would benefit more from looking at an in-depth introduction to R than a quick answer here. This site seems to be a good introduction: https://intro2r.com/index.html . The site recommend RStudio which is far more intuitive and easy to use than base R.
There is also often good documentation on basic functions within R itself. Type ? into the console before any command and it will direct you to some helpful information. For example, you may find these useful to get started.
?hist
?plot
?min
?max

Related

What are the different ways to update an Excel sheet from R

I am in the process of automating a number of graphs that are produced where I work through R that are currently in Excel.
Note that for now, I am not able to convince that doing the graphs directly in R is the best solution, so the solution cannot be "use ggplot2", although I will push for it.
So in the meantime, my path is to download, update and tidy data in R, then export it to an existing Excel file where the graph is already constructed.
The way I have been trying to do that is through openxlsx, which seems to be the most frequent recommendation (for instance here).
However, I am encountering an issue taht I cannot solve with this way (I asked a question there that did not inspire a lot of answers !).
Therefore, I am going to try other ways, but I seem to mainly be directed to the aforementioned solution. What are the existing alternatives ?

Repeatable Macros in R?

Is there any way in R to write a macro like one would in SAS? That is, I want to write a macro with some input variable (corresponding to a row in a dataset) so I can quickly make a plot of certain characteristics from said row. Any information regarding a package/method to do so would be greatly appreciated.
R will generate some very, very, very basic code for you. If you have RStudio installed, you can click File > Import Dataset > From ... point to your file and click 'Open'. R will automatically create the code to do the import. Again, this is very basic. You really need to know how to code to do anything useful.
You get out of it what you put into it, so spend some time learning this stuff, and inevitably you'll learn a ton. I've found that it's very helpful to read through people's questions that are posted here, and try to solve the problem yourself. You'll learn a lot that way and you'll see what the current trends are. Reading books is great, of course, but sometimes I feel like some authors are too academic, and in the real world, sometimes it's done differently than what you see in textbooks.

Namespaces in R packages

How do people learn about giving an R package a namespace? I find the documention in "R Extensions" fine, but I don't really get what is happening when a variable is imported or exported - I need a dummy's guide to these directives.
How do you decide what is exported? Is it just everything that really shouldn't required the pkg:::var syntax? What about imports?
Do imports make it easier to ensure that your use of other package functions doesn't get confused when function names overlap?
Are there special considerations for S4 classes?
Packages that I'm familiar with that use namespaces such as sp and rgdal are quite complicated - are there simple examples that could make things clearer?
I have a start on an answer on the devtools wiki: https://r-pkgs.org/Metadata.html
Few years later here....
I consolidated findings from Chambers, other StackOverflow posts, and lots of tinkering in R:
https://blog.thatbuthow.com/how-r-searches-and-finds-stuff/
This is less about implementing NAMESPACE/IMPORTS/DEPENDS and more about the purpose of these structures. Answers some of your questions.
The clearest explanation I've read is in John Chambers' Software for Data Analysis: Programming with R, page 103. I don't know of any free online explanations that are better than what you've already found in the R Extensions manual.
You could also pick an easy, small package and follow it.
I semi-randomly looked at digest which is one of my smaller packages. I loads a (small) dynamic library and exports one symbol, the digest() function. Here is the content of the NAMESPACE file:
## package has dynamic library
useDynLib(digest)
## and one and only one core function
export(digest)
Have a look at the rest of the source files and maybe try to read Writing R Extensions alongside looking at the example, and do some experiments.
http://www.stat.uiowa.edu/~luke/R/namespaces/morenames.pdf

R code in Sweave

I have a scientific paper under review, and a referee asked for my R code to be provided as a Sweave document. I've never heard of Sweave before, do you know what's the better way to do it?
Thanks a lot :-)
This seems a very unusual request in my opinion. I can understand a referee expecting you to provide reproducible code, but requiring a specific format is over-the-top. I would respond by providing your code. Sweave is not standard practice for academic journals.
A quick google can lead you to a lot of good resources:
http://www.stat.uni-muenchen.de/~leisch/Sweave/
http://www.stat.umn.edu/~charlie/Sweave/
http://jeromyanglim.blogspot.com/2010/02/getting-started-with-sweave-r-latex.html
http://en.wikipedia.org/wiki/Sweave
See my answer to this question: Getting R plots into LaTeX?
I personally recommend using either LyX or Eclipse (with StatET and TeXlipse) for this, although there are many options for editing LaTeX out there.
Edit:
If your script takes a long time to run, then you can also look at the cacheSweave package.

Sample Code for R? [closed]

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Does anyone know a good online resource for example of R code?
The programs do not have to be written for illustrative purposes, I am really just looking for some places where a bunch of R code has been written to give me a sense of the syntax and capabilities of the language?
Edit: I have read the basic documentation on the main site, but was wondering if there was some code samples or even programs that show how R is used by different people.
Why not look at www.r-project.org under documentation and read at least the introduction? The language is sufficiently different from what you're used to that just looking at code samples won't be enough for you to pick it up. (At least, not beyond basic calculator-like functionality.)
If you want to look a bit deeper, you might want to look at CRAN: an online collection of R modules with source code: cran.r-project.org
I just found this question and thought I would add a few resources to it. I really like the Quick-R site:
http://www.statmethods.net/
Muenchen has written a book about using R if you come from SAS or SPSS. Originally it was an 80 page online doc that Springer encouraged him to make a 400+ page book out of. The original short form as well as the book are here:
http://rforsasandspssusers.com/
You've probably already seen these, but worth listing:
http://cran.r-project.org/doc/manuals/R-intro.pdf
http://cran.r-project.org/doc/contrib/Owen-TheRGuide.pdf
http://cran.r-project.org/doc/contrib/Kuhnert+Venables-R_Course_Notes.zip
I don't want to sound like a trite RTFM guy, but the help files generally have great short snips of working code as examples. I'm no R pro so I end up having to deconstruct the examples to understand them. That process, while tedious, is really useful.
Good luck!
EDIT: well I hesitated to be self linking (it feels a bit masturbatory) but here's my own list of R resources with descriptions and comments on each: http://www.cerebralmastication.com/?page_id=62
The Rosetta Code project shows R compared to other languages.
How about CRAN? You've got over a thousand packages of code to choose from.
The simplest way of seeing code, is to
install R
type "help.start()" or look at online documentation, to get names of functions
type the function name at the prompt
This will print the source code right at the prompt, and illustrate all manner of odd and interesting syntax corners.
The Learning R blog has a lot of good examples. Lately, the author has been doing a visualization series, comparing Lattice and ggplot2.
It is hard to google r, because of it being too short a name. Try http://rseek.org/, which provides an r-customized Google search instead. Search on examples, code in repositories, etc.
Some simple examples can be found at Mathesaurus - if you know e.g. Python or Matlab, look at the respective comparison charts to find the R idioms that correspond to your familiar idioms in the other language.
I use the R Graph Gallery. It has been a lot of help on graphing itself. Lots of good examples.
#R on Freenode has also been very useful.
http://had.co.nz/ggplot2/ has a lot of graphics with example code. And you only need one package to create almost every graph you need.
There is also the R Wiki which is slowly growing.
As you probably know, R and S are pretty similar (apart from the cost!).
I use to use both, and I highly recommend S Poetry.
I can also highly recommend the M.J. Crawley book, and the shorter Venables & Ripley one.
here are links to the R project group on Linkedin. I put together this list of links and a lot of people have found it useful (some have also made very useful additions)
Use Google Code Search with command "lang:r" and your keyword(s)
Steve McIntyre at http://www.climateaudit.org/ is a big fan of R and often posts working code.
There is a scripts category, and the Statistics and R lists some other resources

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