Passing function input to name dimnames

I am trying to assign names to list of dimnnames using inputs from an function, but the names only output the function input name (i.e. if function(test1 = "abc)" dimnames outputs "test1", not "abc"). An example function is here:

# example data
set.seed(123)
mcmr <- data.frame(type = rep(c("fm", "xp","mg"), each = 8),
                      teq = rep(c("string","ribbon"),  12),
                      value = sample(0:1, 24, replace = TRUE))

#example function
mcm_fun <- function(technique, test1, test2){
  test1 <- mcmr[mcmr$type == test1 & mcmr$teq == technique, "value"]
  test2 <- mcmr[mcmr$type == test2 & mcmr$teq == technique, "value"]
  matrix(c(table(test1), table(test2)), nrow = 2,
                dimnames = list(test1 = c("Positive", "Negative"), # want to name with test1 input
                                test2 = c("Positive", "Negative"))) # want to name with test2 input
}

Which outputs

mcm_fun("string", "mg", "xp")

#          test2
#test1      Positive Negative
#  Positive        1        3
#  Negative        3        1

The desired output would include the function input for test1 and test2:

#          mg
#xp      Positive Negative
#  Positive        1        3
#  Negative        3        1

I have tried assign() and get() but cant seem to get this to work and all I can seem to find is info on assigning the dimnames themselves.

>Solution :

The labels you’re asking about are the names of the dimnames of the table, so you can set them with:

names(dimnames(m)) <- nms

In your case, just add that assignment step into your function:

mcm_fun <- function(technique, t1, t2){
    test1 <- mcmr[mcmr$type == t1 & mcmr$teq == technique, "value"]
    test2 <- mcmr[mcmr$type == t2 & mcmr$teq == technique, "value"]
    m <- matrix(c(table(test1), table(test2)), nrow = 2,
           dimnames = list(test1 = c("Positive", "Negative"), # want to name with test1 input
                           test2 = c("Positive", "Negative"))) # want to name with test2 input
    names(dimnames(m)) <- c(t1, t2)
    return(m)
}

mcm_fun("string", "mg", "xp")
          xp
mg         Positive Negative
  Positive        3        1
  Negative        1        3

Note that I had to rename your arguments since you were overwriting them with the results of the test.