[R] For loop with multiple iteration indexes

[Albrecht Kauffmann]

Hi,

this simple example is very similarly, and it works in R:

r <- list()
n <- 0
x <- c("a","b","c")#x,y: Data from a dataframe
y <- c("A","B","C")
for (k in 1:3) {
    n <- n+1
    r[[n]] <- paste0(x[k],y[k])#or any other function using x[k] and y[k] as arguments
}
print(r)

Is it this what you meant?

Best,
Albrecht

-- 
  Albrecht Kauffmann
  alkauffm using fastmail.fm

Am Mo, 10. Sep 2018, um 00:49, schrieb David Disabato:
> Hi R-help,
> 
> I am trying to create a for loop with multiple iteration indexes. I don't
> want to use two different for loops nested together because I don't need
> the full matrix of the two indexes, just the diagonal elements (e.g., i[1]
> & j[1] and i[2] & j[2], but not i[1] & j[2]). Is there a way to specify
> both i and j in a single for loop? Here is a simplified example of
> pseudo-code where x and y are equally sized character vectors with column
> names and dat is their dataframe (obviously this code doesn't run in R, but
> hopefully you perceive my goal):
> 
> r <- list()
> n <- 0
> for (i in x; j in y) {
>    n <- n + 1
>    r[[n]] <- cor(x = dat[, i], y = dat[, j])
> }
> print(r)
> 
> I realize there are other solutions to this particular correlation example,
> but my actual problem is much more complicated, so I am hoping for a
> solution that generalizes across any code within the for loop.
> 
> -- 
> David J. Disabato, M.A.
> Clinical Psychology Doctoral Student
> George Mason University
> ddisabat using gmu.edu
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