I have a data frame and one separate vector that is a grouping variable for the
data frame. I would like to take all rows of the data frame belonging to each
group and then sum the columns with out using a for statement.
Something like: take all rows of group 1 then apply(group1.data,1,sum),
?by perhaps
--- Daniel O'Shea [EMAIL PROTECTED] wrote:
I have a data frame and one separate vector that is
a grouping variable for the data frame. I would
like to take all rows of the data frame belonging to
each group and then sum the columns with out using a
for statement.
Something
Here's one way,
lapply(split(DF, your.vector), function(x) {apply(x, 2, sum)})
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Daniel O'Shea
Sent: Tuesday, August 21, 2007 3:53 PM
To: r-help@stat.math.ethz.ch
Subject: [R] summing columns of data
