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R programming

6 messages · varun joshi, Shivi82, Jeff Newmiller +3 more

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varun joshi
# 
Hello there,

I wanted to learn R programming over this summer hence I registered for the
R programming course on Coursera. I understood most part of the lecture but
I'm having a hard time with the assignments.

Till now I can write small functions such as calculating mean of a vector
or an array. I can also use arguments such as lapply, sapply, rbind etc.

I am not very handy with coding in R. I get completely stuck.

What should I do to learn gradually?

Can anyone tell me what to do step by step. I'm an average student pursuing
my masters in Engineering Management at UNC Charlotte.
Shivi82
# 
Hi Varun,

Courses offered from Coursera & EDX are very informative and carry details
in depth. 
However I agree with your point that these courses are very fast paced &
sometimes very technical in nature. (I found the same when I went for Linear
regression course)
I have also recently started learning R and enrolled for free courses at
DataCamp.

DataCamp is fabulous and it really helped me to build a very sound base in
R. There are various courses available ranging from Statistical analysis to
regression, Data analysis, graphical presentation and what not. 
Hence I would highly recommend enrolling for DataCamp without any hiccup.
Once you find you are pretty comfortable with the basics of R you might want
to get enrolled for the paid courses as well as I have done and these course
will only add value to your profile and as an individual.

Happy Learning.
Cheers!!!!
Shivi 



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Jeff Newmiller
# 
Practice (use the str function frequently, print small pieces of complex expressions to understand how they are constructed).

Read the Introduction to R document. Especially the part about indexing.

Read Pat Burns' The R Inferno.

Also remember to post in plain text on this list next time 
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On May 22, 2015 4:01:12 PM PDT, varun joshi <varun1220 at gmail.com> wrote:
Jim Lemon
# 
Hi varun,
A few suggestions.
Learn to use the built in help system, whichever version (text, HTML,
PDF) you prefer.
Learn to use one of the search programs (see
http://cran.r-project.org/search.html)
Try to do every task that you can in R.

Jim
On Sat, May 23, 2015 at 9:01 AM, varun joshi <varun1220 at gmail.com> wrote:
Rich Shepard
#
On Fri, 22 May 2015, varun joshi wrote:

            

      
      
      
    

        
Not sure how one gradually learns; I suppose it depends on what sort of
applications one wants to develop and the most effective means by which one
learns. Regardless, a good place to start is by buying and reading Norman
Matloff's "The Art of R Programming" and following that with Haley Wickham's
"Advanced R".

HTH,

Rich

  
  


  


      

    

    

      
      

        


  

        

      John Kane
    

    

      
      #
    

  


  

      
Read R-help. :) Seriously, you will see all kinds of problems and questions. Some of the simpler ones you can try yourself and see how your approach matches other peoples. 

Google around for some R blogs and see if you find any that are useful. https://learnr.wordpress.com/ might be useful. IIRC there is a mixture of real intro and very sophisticated material there.

Think of something simple exercise or analysis that you would normally do in Matlab or even in a spreadsheet and see how easily you can translate this to R. If needed think more of what you would expect students in first year to be doing if you are a TA and duplicate it in R. 

A great intro to R, in my opinion is Dan Navarro's book (available as a pdf at my last look) but I suspect from your point of view not so good as he is a psychologist and is writing for them. http://health.adelaide.edu.au/psychology/ccs/docs/lsr/lsr-0.3.pdf

With your educational background An Introduction to R may be a good read but, as a non-techie, my normal advise is not to read it right away. It is a fantastic reference and repays reading after a few weeks into R but it is IMHO emphatically NOT an introduction in the same way that the Navarro book is. (I am now changing my name and entering a witness protection program).

Learn as much as possible about the various basic data structures in R.  As someone said use str() a lot.  Here is an example why. Just copy and paste:
dat1  <- structure(list(aa = structure(1:10, .Label = c("1", "2", "3", 
"4", "5", "6", "7", "8", "9", "10"), class = "factor"), bb = c(10L, 
9L, 8L, 7L, 6L, 5L, 4L, 3L, 2L, 1L)), .Names = c("aa", "bb"), row.names = c(NA, 
-10L), class = "data.frame")

dat2  <-  structure(list(aa = 1:10, bb = c(10L, 9L, 8L, 7L, 6L, 5L, 4L, 
3L, 2L, 1L)), .Names = c("aa", "bb"), row.names = c(NA, -10L), class = "data.frame")

dat1
dat2  # looks a lot like dat1 :)


with(dat1, aa*bb)
with(dat2 , aa*bb)

str(dat1)
str(dat2)


BTW dat1 and dat2 are in dput() format which is the preferred way to supply data to the R-help list.  It provides a perfect copy of the data as it sits on your machine and avoids little problems like we see in dat1 vs dat2 if other readers are loading data on their machines.

If the course has not already recommended this, get a good dedicatd R text editor or IDE.  Everyone has their own, but some popular ones seem to be Tinn-R, EMACS, RStudio, and there are many others.

John Kane
Kingston ON Canada

PS: Don't post in HTML. it mangles code.

            

      
      
      
    

        
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