Counting character occurrences in data frame

Thanks Charles, ftable() works perfectly. 

-----Original Message-----
From: Charles C. Berry [mailto:cberry at tajo.ucsd.edu] 
Sent: Tuesday, September 23, 2008 5:06 PM
To: Hutchinson,David [PYR]
Cc: r-help at r-project.org
Subject: Re: [R] Counting character occurrences in data frame



See

 	?ftable
 	?as.data.frame
 	?xtabs

e.g.

 	ftable( xtabs( ~code+year+month, your.df ), col.vars=1 )
 	as.data.frame( xtabs(~code+year+month, your.df ) )

HTH,

Chuck

Hi R-Users,

I have a data frame containing year, month, day, and code columns. The
code column is a unique character of set ('E','A','B') - I am trying

to

determine an efficient way of summarizing the count of each of these
codes by month and year without having to use for...loops and subsets.
Does anyone have any suggestions?

Thanks in advance,
Dave

Here is a snapshot of my data frame:

    year month day code
8006 1935    12   1    E
8007 1935    12   2
8008 1935    12   3    E
8009 1935    12   4
8010 1935    12   5    E
8011 1935    12   6    E

______________________________________________
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.

Charles C. Berry                            (858) 534-2098
                                             Dept of Family/Preventive
Medicine
E mailto:cberry at tajo.ucsd.edu	            UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/  La Jolla, San Diego
92093-0901