[R] Numeric Column Labels in Excel Function

[arun]

HI,

May be you can try:

fun1 <- function(n){
 if(n <=26){
 res <- LETTERS[seq_len(n)]
 }
 else if(n>26 & n <=702){
res <-  c(LETTERS,apply(expand.grid(vec1,vec1)[,2:1],1,paste,collapse=""))[1:n]
}
else if(n >702 & n <=18278){
res <- c(LETTERS,apply(expand.grid(vec1,vec1)[,2:1],1,paste,collapse=""),apply(expand.grid(vec1,vec1,vec1)[,3:1],1,paste,collapse=""))[1:n]
}
else {
NA
}
res
} 
fun1(0)
#character(0)
 fun1(2)
#[1] "A" "B"

fun1(28)
A.K.




On Monday, January 27, 2014 4:41 PM, Dustin Fife <fife.dustin at gmail.com> wrote:
Hi all,

I frequently get requests to do data analysis where the person
references an excel column. e.g., "I want to analyze [insert complex
variable name], located at column AAQ in Excel."  I've been doing is
gsub and inserting a part of the string for the complex variable name,
then going from there. But, I was trying to make function that returns
the following vector:

excelVector = A, B, C, D,...AA, AB, AC...ZA, ZB, ZC,...AAA, AAB, AAC, etc.

In other words, the argument would have one argument (n, or the number
of columns), then it would return a list like that shown above. Then,
all I would have to do is

column.of.interest = which(excelVector=="AAQ")

But I'm a bit stumped. The first part is easy:

LETTERS[1:26]

The next would probably use expand.grid, but all my potential
solutions are pretty clunky.

Any ideas?

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