[R] condense repetitive code for read.csv and rename.vars

[Crombie, Burnette N]

Thanks very much for your contribution, Siraaj.  I appreciate you taking the time to help me learn loops, etc.  BNC

-----Original Message-----
From: Siraaj Khandkar [mailto:siraaj at khandkar.net] 
Sent: Wednesday, August 14, 2013 9:08 PM
To: Crombie, Burnette N
Cc: r-help at r-project.org
Subject: Re: [R] condense repetitive code for read.csv and rename.vars

On 08/14/2013 03:43 PM, bcrombie wrote:
> Is there a more concise way to write the following code?
>
> library(gdata)
> mydataOUTPUTrtfA <- read.csv("mergedStatstA.csv") 
> save(mydataOUTPUTrtfA, file="mydataOUTPUTrtfA.RData") mydataOUTPUTrtfA 
> <- rename.vars(mydataOUTPUTrtfA, from="X", to="Statistics.Calculated", 
> info=FALSE)
>
> mydataOUTPUTrtfB <- read.csv("mergedStatstB.csv") 
> save(mydataOUTPUTrtfB, file="mydataOUTPUTrtfB.RData") mydataOUTPUTrtfB 
> <- rename.vars(mydataOUTPUTrtfB, from="X", to="Statistics.Calculated", 
> info=FALSE)
>
> mydataOUTPUTrtfC <- read.csv("mergedStatstC.csv") 
> save(mydataOUTPUTrtfC, file="mydataOUTPUTrtfC.RData") mydataOUTPUTrtfC 
> <- rename.vars(mydataOUTPUTrtfC, from="X", to="Statistics.Calculated", 
> info=FALSE)
>
> I will have a series of mydataOUTPUTrtf files spanning a large portion 
> of the alphabet, so to speak:
> e.g. mydataOUTPUTrtfA to mydataOUTPUTrtfG  --- thanks for your help
>

   alphabet <- c("FOO", "BAR", "BAZ")

   for (a in alphabet) {
     filename <- paste(c("basename", a, ".csv"), collapse="")
     data <- read.csv(filename)
     date <- rename.vars( data
                        , from="X"
                        , to="Statistics.Calculated"
                        , info=FALSE
                        )
     # do some other stuff with data
   }


You should be able to pick it up from here.

In case you need an actual alphabet, it is already predefined:

 > LETTERS
  [1] "A" "B" "C" "D" "E" "F" "G" "H" "I" "J" "K" "L" "M" "N" "O" "P" "Q"
[18] "R" "S" "T" "U" "V" "W" "X" "Y" "Z"
 > letters
  [1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l" "m" "n" "o" "p" "q"
[18] "r" "s" "t" "u" "v" "w" "x" "y" "z"
 >