On Dec 11, 2009, at 4:38 PM, Jose Narillos de Santos wrote:
Hi all,
Imagine I have a matrix and the first colum is a list that repeats
the same
names, I want to sum the second column on each unique name on first
column.
Imagine this:
Pepe 2
Pepe 3
Pepe 4
Jose 2
Jose 5
Manuel 4
Manuel 2
?tapply # or one of its derivative fucntions like by or aggregate
I want to make a new matrix that calculates and recognizes that
there are 3
different names ans sum second column. But a priori I don´t know the
list of
the different names:
In my example
Something like:
tapply(valuecol, namecol, sum)
(Untested.)
Pepe 9
Jose 7
Manuel 6
I´m trying to use something like sapply or apply but I can find the
key...
Can anyone help or guide me ?
Thanks in advance¡¡¡
[[alternative HTML version deleted]]
______________________________________________
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
Heritage Laboratories
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.
