How use crosstab with apply or sapply function

Question

I am struggling with using the crosstab function, available at the link:

source("http://pcwww.liv.ac.uk/~william/R/crosstab.r")

I have also used the gtsummary library and converted mtcars to a tibble, then converted the vs and am columns to characters using:

library(gtsummary)
mtcars = mtcars %>% as_tibble()
mtcars = apply(mtcars %>% select(vs, am), 2, as.character)

crosstab(mtcars, row.vars = "vs")
crosstab(mtcars, row.vars = "am")

I would like to achieve the same using the apply or sapply function, without using the crosstab function's row.vars argument, which I do not know how to set.

I have tried

apply(mtcars, 2, crosstab(mtcars, row.vars = c('vs', 'am')))

But it does not work. Is there an alternative way to achieve this, even with the sapply function?

Thanks.

what is your desired output? can you edit the question and add an example? — user12256545, Jun 16 '23 at 12:48
yes. Please check what returns the function separately on the interested variable. I have edited the post — 12666727b9, Jun 16 '23 at 12:49
it really does. Thanks could you explain a bit about the utility of the `\` mark? — 12666727b9, Jun 16 '23 at 13:03
single quotation marks (') function the same as double ones (") in this case . They can be useful if you have one type of quotation in a sting , ie 'a string with "aqoute" inside' — user12256545, Jun 16 '23 at 13:07
sorry, there was this missing symbol within those \. I do know why it was converted like that. — 12666727b9, Jun 16 '23 at 13:13

score 1 · Accepted Answer · answered Jun 16 '23 at 12:58

Hi you almost got it right, you just got confused with the apply syntax:

You want to iterate over a list of column names (variables) instead of the dataframe and pass this as the row.vars argument.

lapply(c('vs', 'am'),\(col) crosstab(mtcars, row.vars = col))
sapply(c('vs', 'am'),\(col) crosstab(mtcars, row.vars = col),simplify = F)

The equivalent for loop would be:

for (col in c('vs', 'am')) {
  crosstab(mtcars,row.vars = col)|>print()
}

How use crosstab with apply or sapply function

1 Answers1