[Rd] ftable.formula

[Timothy Bates]

At least this is correct :-)

 ftable(UCBAdmissions, Dept ~ Gender + Admit)

But yes: the formula
ftable(UCBAdmissions, Gender + Admit ~ Dept)

should see "The left and right hand side of formula specify the column and row variables, respectively"

# demo of right-hand side bug

ftable(UCBAdmissions, Gender + Admit ~ Dept) # "Dept" should be in the rows...
                Dept   A   B   C   D   E   F
Admit    Gender                             
Admitted Male        512 353 120 138  53  22
         Female       89  17 202 131  94  24
Rejected Male        313 207 205 279 138 351
         Female       19   8 391 244 299 317


Also, the example appears not to be a correct use of the "." shortcut.

x <- ftable(Survived ~ ., data = Titanic)
# Error in ftable.formula(Survived ~ ., data = Titanic) : 
#  cannot use dots in formula with given data

Also "Survived" should be "survived"
And in this example, all vars should be lower-case

ftable(Sex ~ Class + Age, data = x)

t

On 26 Jan 2012, at 22:31, Brett Presnell wrote:
> From reading the documentation for ftable.formula, I expected that the
> following two calls to ftable would produce the same results:
> 
> data(UCBAdmissions)
> ftable(UCBAdmissions, row.vars = "Dept", col.vars = c("Gender", "Admit"))
> ftable(UCBAdmissions, Gender + Admit ~ Dept)
> 
> Is this a bug or the intended behavior?  I prefer the formula interface,
> so I would be happiest if the output was the same for the two calls.
> However, if this is the intended behavior, then I think that the
> documentation should be clearer on this point.