[R] don't want xtab sorting "numeric" factors...

[Jeff D. Hamann]

r-gurus,

I couldn't find an answer to this and after an hour or so of trying all
types or ways to do this, I've given up for now.

I'm having trouble getting the results from xtabs to generate
"unsorted" factors. I've generated a sample data.frame I want to
create a table from, using xtabs, and the results are presented below,

> temp
   treatment itpa       qmd      tht
1          0  100  7.287263 3.362501
2         25  100 10.461070 4.118217
3         50  100 16.671731 5.814391
4         75  100 24.033238 8.264608
5        100  100 27.554497 9.586341
6          0  200  7.032527 3.355118
7         25  200  9.632828 4.039846
8         50  200 14.821584 5.659913
9         75  200 20.470692 7.791525
10       100  200 22.977827 8.901247
11         0  300  6.839360 3.355788
12        25  300  9.437649 4.070102
13        50  300 13.609004 5.545991
14        75  300 18.159601 7.387135
15       100  300 20.194335 8.380818
16         0  600  6.232509 3.330317
17        25  600  8.371084 3.990557
18        50  600 11.512385 5.235263
19        75  600 14.463214 6.605290
20       100  600 16.030137 7.467160
21         0  900  5.938640 3.338342
22        25  900  7.610695 3.891203
23        50  900 10.209530 4.917330
24        75  900 12.528651 6.157436
25       100  900 13.708622 6.791764
26         0 1200  5.841058 3.389716
27        25 1200  7.174748 3.859241
28        50 1200  9.238635 4.689011
29        75 1200 11.424713 5.688340
30       100 1200 12.349254 6.275864
> t <- xtabs( temp$tht ~ temp$itpa + temp$treatment )

t <- xtabs( temp$tht ~ temp$itpa + temp$treatment )
>
> t
         temp$treatment
temp$itpa        0      100       25       50       75
     100  3.362501 9.586341 4.118217 5.814391 8.264608
     1200 3.389716 6.275864 3.859241 4.689011 5.688340
     200  3.355118 8.901247 4.039846 5.659913 7.791525
     300  3.355788 8.380818 4.070102 5.545991 7.387135
     600  3.330317 7.467160 3.990557 5.235263 6.605290
     900  3.338342 6.791764 3.891203 4.917330 6.157436
>

the factors represent real values and shouldn't be sorted as
strings. The table should read,

> t
         temp$treatment
temp$itpa        0       25       50       75      100
     100  3.362501 4.118217 5.814391 8.264608 9.586341
     200  3.355118 4.039846 5.659913 7.791525 8.901247
     300  3.355788 4.070102 5.545991 7.387135 8.380818
     600  3.330317 3.990557 5.235263 6.605290 7.467160
     900  3.338342 3.891203 4.917330 6.157436 6.791764
     1200 3.389716 3.859241 4.689011 5.688340 6.275864
>

this wouldn't be that big of an issue if I only did this once for the
results, but I'm using this in Sweave and need create the tables after
thousands of iterations.

Any help would be greatly appreciated.

Thanks,
Jeff.

-- 
Jeff D. Hamann
Forest Informatics, Inc.
PO Box 1421
Corvallis, Oregon 97339-1421
phone 541-754-1428
fax 541-752-0288
jeff.hamann at forestinformatics.com
www.forestinformatics.com