I'm not sure I understand what you want but you might like to try
"aggregate"
Regards
Ross Darnell
-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of Karin Lagesen
Sent: Thursday, 11 October 2007 7:05 PM
To: r-help at r-project.org
Subject: [R] creating summary functions for data frame
I have a data frame that looks like this:
> gctablechromonly[1:5,]
refseq geometry gccontent X60_origin X60_terminus length kingdom
1 NC_009484 cir 0.6799 1790000 773000 3389227 Bacteria
2 NC_009484 cir 0.6799 1790000 773000 3389227 Bacteria
3 NC_009484 cir 0.6799 1790000 773000 3389227 Bacteria
4 NC_009484 cir 0.6799 1790000 773000 3389227 Bacteria
5 NC_009484 cir 0.6799 1790000 773000 3389227 Bacteria
grp feature gene begin dir gc_content replicor LEADLAG
1 Alphaproteobacteria CDS CDS 261 + 0.654244 RIGHT LEAD
2 Alphaproteobacteria CDS CDS 1737 - 0.651408 RIGHT LAG
3 Alphaproteobacteria CDS CDS 2902 + 0.607843 RIGHT LEAD
4 Alphaproteobacteria CDS CDS 3693 + 0.617647 RIGHT LEAD
5 Alphaproteobacteria CDS CDS 4227 + 0.699208 RIGHT
LEAD>
About half of these columns are factors, for instance refseq, kingdom,
grp and feature.
Now, I have seen that I can do
by(gctablechromonly, gctablechromonly$feature, summary)
to get useful information.
However, I a wondering how I can write my own functions to get what
I'd like. For instance, how could I get a table with grp as rows down
the right, feature on the top, and a count of each kind of feature
within each grp?
I realize that this is probably pretty easy to do, but I do not know
enough R yet to know which words to look for in the mail archives...:)
TIA,
Karin
--
Karin Lagesen, PhD student
karin.lagesen at medisin.uio.no
http://folk.uio.no/karinlag
______________________________________________
R-help at 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.