On Jul 9, 2010, at 10:26 AM, Eik Vettorazzi wrote:
you are right. But maybe "aggregate" is close to the desired result?
aggregate(bla, list(bla$cat), max)
Right. I couldn't get it to work until I removed the first two columns:
aggregate(bla[,-(1:2)], list(bla$cat), max)
Then I got pretty much the same dataframe as I would have with :
as.data.frame(lapply( bla[, -(1:2)], function(x) tapply(x, bla$cat,
max) ))
v1 v2 v3 v4
cat1 0.4634519 0.5274645 0.6051479 0.7586322
cat2 0.4062700 0.4282639 0.4443707 0.8419526
cat3 0.4816403 0.4996033 0.3538144 0.9456385
cat4 0.6354560 0.3558259 0.3646292 0.1907295
cat5 0.6663811 0.2154201 0.5059900 0.7573575
cat6 0.5260832 0.3934063 0.3545962 0.6412563
Except that aggregate version returns it with a "Group.1" column of
"cat"s while the other version returned it with the "cat" names in the
rownames. A matter of taste?
--
David.
Am 09.07.2010 16:01, schrieb David Winsemius:
On Jul 9, 2010, at 9:46 AM, Eik Vettorazzi wrote:
Hi Nils,
have a look at
?tapply
hth.
Perhaps this will be part way there (I couldn't really figure out the
desired structure of the final object):
lapply( bla[, -(1:2)], function(x) tapply(x, bla$cat, max) )
$v1
cat1 cat2 cat3 cat4 cat5 cat6
0.4634519 0.4062700 0.4816403 0.6354560 0.6663811 0.5260832
$v2
cat1 cat2 cat3 cat4 cat5 cat6
0.5274645 0.4282639 0.4996033 0.3558259 0.2154201 0.3934063
$v3
cat1 cat2 cat3 cat4 cat5 cat6
0.6051479 0.4443707 0.3538144 0.3646292 0.5059900 0.3545962
$v4
cat1 cat2 cat3 cat4 cat5 cat6
0.7586322 0.8419526 0.9456385 0.1907295 0.7573575 0.6412563
Am 09.07.2010 15:37, schrieb LogLord:
Hi,
I would like to assign the largest value of a column to a specific
category
and repeat this for each column (v1 - v4).
x=c(1:12)
cat
=
c
("cat1
","cat5
","cat2
","cat2","cat1","cat5","cat3","cat4","cat5","cat2","cat3","cat6")
v1=rnorm(12,0.5,0.1)
v2=rnorm(12,0.3,0.2)
v3=rnorm(12,0.4,0.1)
v4=rnorm(12,0.6,0.3)
bla=data.frame(x,cat,v1,v2,v3,v4)
bla
x cat v1 v2 v3 v4
1 1 cat1 0.4013144 0.54839317 0.3946393 0.8679266
2 2 cat5 0.4595873 0.45788906 0.4030078 0.5919596
3 3 cat2 0.4542865 0.21516928 0.2777649 0.6112099
4 4 cat2 0.4787950 0.06252512 0.5095611 0.6450795
5 5 cat1 0.4910746 0.56591049 0.5151813 0.8465181
6 6 cat5 0.4194397 0.16592579 0.4361643 0.6415192
7 7 cat3 0.6148564 0.32240342 0.2690108 0.7114133
8 8 cat4 0.6174652 0.28076152 0.4577064 -0.2567284
9 9 cat5 0.4775395 0.28611768 0.4660210 0.4634120
10 10 cat2 0.4802962 0.03715569 0.4506361 1.0063235
11 11 cat3 0.6495094 0.33303172 0.3352933 1.4390324
12 12 cat6 0.4891481 0.45355589 0.3880739 0.7831656
I can assign this by the sqldf() command for each column but I
would
like to
automate this as I have many columns.
select=sqldf("select cat, max(v1) FROM bla GROUP BY cat")
select
cat max(v1)
1 cat1 0.4910746
2 cat2 0.4802962
3 cat3 0.6495094
4 cat4 0.6174652
5 cat5 0.4775395
6 cat6 0.4891481
Finally, I would like to have a dataframe where where the cat is
followed by
each column maximum.
Thanks for your help!
--
Eik Vettorazzi
Institut für Medizinische Biometrie und Epidemiologie
Universitätsklinikum Hamburg-Eppendorf
Martinistr. 52
20246 Hamburg
T ++49/40/7410-58243
F ++49/40/7410-57790
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
David Winsemius, MD
West Hartford, CT
--
Eik Vettorazzi
Institut für Medizinische Biometrie und Epidemiologie
Universitätsklinikum Hamburg-Eppendorf
Martinistr. 52
20246 Hamburg
T ++49/40/7410-58243
F ++49/40/7410-57790
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
David Winsemius, MD
West Hartford, CT
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
