[R] ftable and data.frame

[David Winsemius]

On Dec 20, 2013, at 5:01 AM, <silvano at uel.br> wrote:

> Hi,
> 
> I used this command to produce a table:

It's not actually a 'table'.

> 
> (tab1 = ftable(SEX, ESTCIV, Q1))

is.table(tab1) # will return FALSE

> 
>                               Q1  B  L  M  N
> SEXO    ESTCIV
>        F           A         11 13  4  2
>                      E          1  0  0  0
>        M           A          5  0  3  1
>                      E          0  0  0  0
> 
> but I need something like:
> 
> 
> SEXO    ESTCIV        B  L  M  N
>      F            A         11 13  4  2
>      F            E          1  0  0  0
>      M           A          5  0  3  1
>      M           E          0  0  0  0
> 
> How can I get it?

You need to describe the purpose of this effort. 

If is for display, the answer will be to look at the code for `print.ftable` (which eventually passes its arguments to `format.ftable`.

If it is for creating something other than an ftable (such a data.frame or character-matrix), then you will probably need to coerce the ftable to a matrix to get the entry values and then extract the row labels from the 'tab1'-object with:   attr(tab1, "row.vars") and `rep` them approriately. Or you could work with the output from format(ftable(tab1))[ ,1:2].

cbind( format(ftable(Titanic), quote=FALSE)[ ,1:3], 
       format(ftable(Titanic), quote=FALSE)[ ,5:6])
      [,1]    [,2]     [,3]    [,4]  [,5] 
 [1,] "     " "      " "     " " No" "Yes"
 [2,] "Class" "Sex   " "Age  " "   " "   "
 [3,] "1st  " "Male  " "Child" "  0" "  5"
 [4,] "     " "      " "Adult" "118" " 57"
 [5,] "     " "Female" "Child" "  0" "  1"
 [6,] "     " "      " "Adult" "  4" "140"
 [7,] "2nd  " "Male  " "Child" "  0" " 11"
 [8,] "     " "      " "Adult" "154" " 14"
 [9,] "     " "Female" "Child" "  0" " 13"
[10,] "     " "      " "Adult" " 13" " 80"
[11,] "3rd  " "Male  " "Child" " 35" " 13"
[12,] "     " "      " "Adult" "387" " 75"
[13,] "     " "Female" "Child" " 17" " 14"
[14,] "     " "      " "Adult" " 89" " 76"
[15,] "Crew " "Male  " "Child" "  0" "  0"
[16,] "     " "      " "Adult" "670" "192"
[17,] "     " "Female" "Child" "  0" "  0"
[18,] "     " "      " "Adult" "  3" " 20"

> 
> I need this format to use ordinal logistic regression and I have many tables.

That makes me think using ftable is the completely misguided approach. You should describe in more detail you plans to use ordinal logistic regression. I'm also wondering if you have used attach(). It would make more sense to keep these variables in a dataframe. Almost all regression functions expect input in the form of a normalized dataframe rather than in separate variables of aggregated counts.


> (tab1 = ftable(SEX, ESTCIV, Q1))
> 
> Thanks,
> 
> Silvano.
> 
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David Winsemius
Alameda, CA, USA