Message-ID: <07773E68C32A644CA47651463E79E5C20247725F@CCHSCLEXMB68.cc.ad.cchs.net>
Date: 2009-03-12T13:16:37Z
From: Nutter, Benjamin
Subject: help with loop
In-Reply-To: <648801.99056.qm@web31605.mail.mud.yahoo.com>
Why use a loop? Try using diff()
x <- c(4, 19, 21, 45, 50, 73, 78, 83, 87, 94)
sum(diff(x))
-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of Rafael Moral
Sent: Thursday, March 12, 2009 9:04 AM
To: r-help at r-project.org
Subject: [R] help with loop
Dear?useRs,
I'm trying to write a loop to?sum my data in the following way:
(the second?- the first) + (the third - the second) + (the fourth - the third) + ...
for each column.
So, I wrote something like this:
? c <- list()
? for(i in 1:ncol(mydata)) {
? for(j in 2:nrow(mydata)) {
? c[[i]] <- sum(yc[j,i] - yc[(j-1),i])
? }}}
As for the columns it works pretty fine, but it only returns the last subtraction, however, I need the sum of all subtractions.
Any ideas?
Regards,
Rafael.
Veja quais s?o os assuntos do momento no Yahoo! +Buscados
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