[R] Summary stats in table

[Duncan Murdoch]

On 11-10-24 7:16 PM, Hadley Wickham wrote:
> On Mon, Oct 24, 2011 at 5:39 AM, Duncan Murdoch
> <murdoch.duncan at gmail.com>  wrote:
>> Suppose I have data like this:
>>
>> A<- sample(letters[1:3], 1000, replace=TRUE)
>> B<- sample(LETTERS[1:2], 1000, replace=TRUE)
>> x<- rnorm(1000)
>>
>> I can get a table of means via
>>
>> tapply(x, list(A, B), mean)
>>
>> and I can add the marginal means to this using cbind/rbind:
>>
>> main<- tapply(x, list(A,B), mean)
>> Amargin<- tapply(x, list(A), mean)
>> Bmargin<- tapply(x, list(B), mean)
>>
>> rbind(cbind(main, all=Amargin),all=c(Bmargin, mean(x)))
>>
>> But this is tedious.  Has some package got some code that makes this easier?
>
> Have a look at reshape2::add_margins - it's not super efficient, but I
> think cool because it works for arbitrarily many dimensions.
>
> Hadley
>

I actually was hoping for something more like what I remember vaguely 
from SAS PROC TABULATE, which I haven't used in about 20 years.  Anyway, 
I decided to go ahead and write it; it's fun enough that I'll probably 
put it on CRAN eventually.  Here's what it currently gives:

 > tabular( x*mean*(A+1) ~ (B+1) )

               B
               A       B        All
  x mean A a   0.05058  0.02308  0.036279
           b   0.02878  0.01188  0.020953
           c   0.06869 -0.08192 -0.003033
           All 0.04906 -0.01511  0.017875


and here's a more elaborate example:

 > example(tabular)

tabulr> tabular( (Species + 1) ~ (n=1) + Format(digits=2)*
tabulr+          (Sepal.Length + Sepal.Width)*(mean + sd), data=iris )

                         Sepal.Length      Sepal.Width
                     n   mean         sd   mean        sd
  Species setosa      50 5.01         0.35 3.43        0.38
          versicolor  50 5.94         0.52 2.77        0.31
          virginica   50 6.59         0.64 2.97        0.32
          All        150 5.84         0.83 3.06        0.44


Duncan Murdoch